diff --git a/finetune/prepare_buckets_latents.py b/finetune/prepare_buckets_latents.py
index 0389da38..019c737a 100644
--- a/finetune/prepare_buckets_latents.py
+++ b/finetune/prepare_buckets_latents.py
@@ -11,6 +11,7 @@ import cv2
 
 import torch
 from library.device_utils import init_ipex, get_preferred_device
+
 init_ipex()
 
 from torchvision import transforms
@@ -18,8 +19,10 @@ from torchvision import transforms
 import library.model_util as model_util
 import library.train_util as train_util
 from library.utils import setup_logging
+
 setup_logging()
 import logging
+
 logger = logging.getLogger(__name__)
 
 DEVICE = get_preferred_device()
@@ -89,7 +92,9 @@ def main(args):
 
     # bucketのサイズを計算する
     max_reso = tuple([int(t) for t in args.max_resolution.split(",")])
-    assert len(max_reso) == 2, f"illegal resolution (not 'width,height') / 画像サイズに誤りがあります。'幅,高さ'で指定してください: {args.max_resolution}"
+    assert (
+        len(max_reso) == 2
+    ), f"illegal resolution (not 'width,height') / 画像サイズに誤りがあります。'幅,高さ'で指定してください: {args.max_resolution}"
 
     bucket_manager = train_util.BucketManager(
         args.bucket_no_upscale, max_reso, args.min_bucket_reso, args.max_bucket_reso, args.bucket_reso_steps
@@ -107,7 +112,7 @@ def main(args):
     def process_batch(is_last):
         for bucket in bucket_manager.buckets:
             if (is_last and len(bucket) > 0) or len(bucket) >= args.batch_size:
-                train_util.cache_batch_latents(vae, True, bucket, args.flip_aug, False)
+                train_util.cache_batch_latents(vae, True, bucket, args.flip_aug, args.alpha_mask, False)
                 bucket.clear()
 
     # 読み込みの高速化のためにDataLoaderを使うオプション
@@ -208,7 +213,9 @@ def setup_parser() -> argparse.ArgumentParser:
     parser.add_argument("in_json", type=str, help="metadata file to input / 読み込むメタデータファイル")
     parser.add_argument("out_json", type=str, help="metadata file to output / メタデータファイル書き出し先")
     parser.add_argument("model_name_or_path", type=str, help="model name or path to encode latents / latentを取得するためのモデル")
-    parser.add_argument("--v2", action="store_true", help="not used (for backward compatibility) / 使用されません（互換性のため残してあります）")
+    parser.add_argument(
+        "--v2", action="store_true", help="not used (for backward compatibility) / 使用されません（互換性のため残してあります）"
+    )
     parser.add_argument("--batch_size", type=int, default=1, help="batch size in inference / 推論時のバッチサイズ")
     parser.add_argument(
         "--max_data_loader_n_workers",
@@ -231,10 +238,16 @@ def setup_parser() -> argparse.ArgumentParser:
         help="steps of resolution for buckets, divisible by 8 is recommended / bucketの解像度の単位、8で割り切れる値を推奨します",
     )
     parser.add_argument(
-        "--bucket_no_upscale", action="store_true", help="make bucket for each image without upscaling / 画像を拡大せずbucketを作成します"
+        "--bucket_no_upscale",
+        action="store_true",
+        help="make bucket for each image without upscaling / 画像を拡大せずbucketを作成します",
     )
     parser.add_argument(
-        "--mixed_precision", type=str, default="no", choices=["no", "fp16", "bf16"], help="use mixed precision / 混合精度を使う場合、その精度"
+        "--mixed_precision",
+        type=str,
+        default="no",
+        choices=["no", "fp16", "bf16"],
+        help="use mixed precision / 混合精度を使う場合、その精度",
     )
     parser.add_argument(
         "--full_path",
@@ -242,7 +255,15 @@ def setup_parser() -> argparse.ArgumentParser:
         help="use full path as image-key in metadata (supports multiple directories) / メタデータで画像キーをフルパスにする（複数の学習画像ディレクトリに対応）",
     )
     parser.add_argument(
-        "--flip_aug", action="store_true", help="flip augmentation, save latents for flipped images / 左右反転した画像もlatentを取得、保存する"
+        "--flip_aug",
+        action="store_true",
+        help="flip augmentation, save latents for flipped images / 左右反転した画像もlatentを取得、保存する",
+    )
+    parser.add_argument(
+        "--alpha_mask",
+        type=str,
+        default="",
+        help="save alpha mask for images for loss calculation / 損失計算用に画像のアルファマスクを保存する",
     )
     parser.add_argument(
         "--skip_existing",
diff --git a/library/config_util.py b/library/config_util.py
index 82baab83..964270db 100644
--- a/library/config_util.py
+++ b/library/config_util.py
@@ -214,11 +214,13 @@ class ConfigSanitizer:
     DB_SUBSET_DISTINCT_SCHEMA = {
         Required("image_dir"): str,
         "is_reg": bool,
+        "alpha_mask": bool,
     }
     # FT means FineTuning
     FT_SUBSET_DISTINCT_SCHEMA = {
         Required("metadata_file"): str,
         "image_dir": str,
+        "alpha_mask": bool,
     }
     CN_SUBSET_ASCENDABLE_SCHEMA = {
         "caption_extension": str,
diff --git a/library/custom_train_functions.py b/library/custom_train_functions.py
index fad12740..af5813a1 100644
--- a/library/custom_train_functions.py
+++ b/library/custom_train_functions.py
@@ -479,14 +479,19 @@ def apply_noise_offset(latents, noise, noise_offset, adaptive_noise_scale):
     return noise
 
 
-def apply_masked_loss(loss, mask_image):
-    # mask image is -1 to 1. we need to convert it to 0 to 1
-    # mask_image = batch["conditioning_images"].to(dtype=loss.dtype)[:, 0].unsqueeze(1)  # use R channel
-    mask_image = mask_image.to(dtype=loss.dtype)
+def apply_masked_loss(loss, batch):
+    if "conditioning_images" in batch:
+        # conditioning image is -1 to 1. we need to convert it to 0 to 1
+        mask_image = batch["conditioning_images"].to(dtype=loss.dtype)[:, 0].unsqueeze(1)  # use R channel
+        mask_image = mask_image / 2 + 0.5
+    elif "alpha_masks" in batch and batch["alpha_masks"] is not None:
+        # alpha mask is 0 to 1
+        mask_image = batch["alpha_masks"].to(dtype=loss.dtype)
+    else:
+        return loss
 
     # resize to the same size as the loss
     mask_image = torch.nn.functional.interpolate(mask_image, size=loss.shape[2:], mode="area")
-    mask_image = mask_image / 2 + 0.5
     loss = loss * mask_image
     return loss
 
diff --git a/library/train_util.py b/library/train_util.py
index 6cf28590..e7a50f04 100644
--- a/library/train_util.py
+++ b/library/train_util.py
@@ -159,9 +159,7 @@ class ImageInfo:
         self.text_encoder_outputs1: Optional[torch.Tensor] = None
         self.text_encoder_outputs2: Optional[torch.Tensor] = None
         self.text_encoder_pool2: Optional[torch.Tensor] = None
-        self.alpha_mask: Optional[torch.Tensor] = None
-        self.alpha_mask_flipped: Optional[torch.Tensor] = None
-        self.use_alpha_mask: bool = False
+        self.alpha_mask: Optional[torch.Tensor] = None  # alpha mask can be flipped in runtime
 
 
 class BucketManager:
@@ -364,6 +362,7 @@ class BaseSubset:
     def __init__(
         self,
         image_dir: Optional[str],
+        alpha_mask: Optional[bool],
         num_repeats: int,
         shuffle_caption: bool,
         caption_separator: str,
@@ -382,9 +381,9 @@ class BaseSubset:
         caption_suffix: Optional[str],
         token_warmup_min: int,
         token_warmup_step: Union[float, int],
-        alpha_mask: bool,
     ) -> None:
         self.image_dir = image_dir
+        self.alpha_mask = alpha_mask if alpha_mask is not None else False
         self.num_repeats = num_repeats
         self.shuffle_caption = shuffle_caption
         self.caption_separator = caption_separator
@@ -407,8 +406,6 @@ class BaseSubset:
 
         self.img_count = 0
 
-        self.alpha_mask = alpha_mask
-
 
 class DreamBoothSubset(BaseSubset):
     def __init__(
@@ -418,6 +415,7 @@ class DreamBoothSubset(BaseSubset):
         class_tokens: Optional[str],
         caption_extension: str,
         cache_info: bool,
+        alpha_mask: bool,
         num_repeats,
         shuffle_caption,
         caption_separator: str,
@@ -441,6 +439,7 @@ class DreamBoothSubset(BaseSubset):
 
         super().__init__(
             image_dir,
+            alpha_mask,
             num_repeats,
             shuffle_caption,
             caption_separator,
@@ -479,6 +478,7 @@ class FineTuningSubset(BaseSubset):
         self,
         image_dir,
         metadata_file: str,
+        alpha_mask: bool,
         num_repeats,
         shuffle_caption,
         caption_separator,
@@ -502,6 +502,7 @@ class FineTuningSubset(BaseSubset):
 
         super().__init__(
             image_dir,
+            alpha_mask,
             num_repeats,
             shuffle_caption,
             caption_separator,
@@ -921,7 +922,7 @@ class BaseDataset(torch.utils.data.Dataset):
             logger.info(f"mean ar error (without repeats): {mean_img_ar_error}")
 
         # データ参照用indexを作る。このindexはdatasetのshuffleに用いられる
-        self.buckets_indices: List(BucketBatchIndex) = []
+        self.buckets_indices: List[BucketBatchIndex] = []
         for bucket_index, bucket in enumerate(self.bucket_manager.buckets):
             batch_count = int(math.ceil(len(bucket) / self.batch_size))
             for batch_index in range(batch_count):
@@ -991,8 +992,6 @@ class BaseDataset(torch.utils.data.Dataset):
         for info in tqdm(image_infos):
             subset = self.image_to_subset[info.image_key]
 
-            info.use_alpha_mask = subset.alpha_mask
-
             if info.latents_npz is not None:  # fine tuning dataset
                 continue
 
@@ -1002,7 +1001,9 @@ class BaseDataset(torch.utils.data.Dataset):
                 if not is_main_process:  # store to info only
                     continue
 
-                cache_available = is_disk_cached_latents_is_expected(info.bucket_reso, info.latents_npz, subset.flip_aug)
+                cache_available = is_disk_cached_latents_is_expected(
+                    info.bucket_reso, info.latents_npz, subset.flip_aug, subset.alpha_mask
+                )
 
                 if cache_available:  # do not add to batch
                     continue
@@ -1028,7 +1029,7 @@ class BaseDataset(torch.utils.data.Dataset):
         # iterate batches: batch doesn't have image, image will be loaded in cache_batch_latents and discarded
         logger.info("caching latents...")
         for batch in tqdm(batches, smoothing=1, total=len(batches)):
-            cache_batch_latents(vae, cache_to_disk, batch, subset.flip_aug, subset.random_crop)
+            cache_batch_latents(vae, cache_to_disk, batch, subset.flip_aug, subset.alpha_mask, subset.random_crop)
 
     # weight_dtypeを指定するとText Encoderそのもの、およひ出力がweight_dtypeになる
     # SDXLでのみ有効だが、datasetのメソッドとする必要があるので、sdxl_train_util.pyではなくこちらに実装する
@@ -1202,18 +1203,15 @@ class BaseDataset(torch.utils.data.Dataset):
                     alpha_mask = image_info.alpha_mask
                 else:
                     latents = image_info.latents_flipped
-                    alpha_mask = image_info.alpha_mask_flipped
+                    alpha_mask = None if image_info.alpha_mask is None else torch.flip(image_info.alpha_mask, [1])
 
                 image = None
             elif image_info.latents_npz is not None:  # FineTuningDatasetまたはcache_latents_to_disk=Trueの場合
-                latents, original_size, crop_ltrb, flipped_latents, alpha_mask, flipped_alpha_mask = load_latents_from_disk(
-                    image_info.latents_npz
-                )
+                latents, original_size, crop_ltrb, flipped_latents, alpha_mask = load_latents_from_disk(image_info.latents_npz)
                 if flipped:
                     latents = flipped_latents
-                    alpha_mask = flipped_alpha_mask
+                    alpha_mask = None if alpha_mask is None else alpha_mask[:, ::-1].copy()  # copy to avoid negative stride problem
                     del flipped_latents
-                    del flipped_alpha_mask
                 latents = torch.FloatTensor(latents)
                 if alpha_mask is not None:
                     alpha_mask = torch.FloatTensor(alpha_mask)
@@ -1255,23 +1253,28 @@ class BaseDataset(torch.utils.data.Dataset):
                 # augmentation
                 aug = self.aug_helper.get_augmentor(subset.color_aug)
                 if aug is not None:
-                    img = aug(image=img)["image"]
+                    # augment RGB channels only
+                    img_rgb = img[:, :, :3]
+                    img_rgb = aug(image=img_rgb)["image"]
+                    img[:, :, :3] = img_rgb
 
                 if flipped:
                     img = img[:, ::-1, :].copy()  # copy to avoid negative stride problem
 
                 if subset.alpha_mask:
                     if img.shape[2] == 4:
-                        alpha_mask = img[:, :, 3]  # [W,H]
+                        alpha_mask = img[:, :, 3]  # [H,W]
+                        alpha_mask = transforms.ToTensor()(alpha_mask)  # 0-255 -> 0-1
                     else:
-                        alpha_mask = np.full((im_w, im_h), 255, dtype=np.uint8)  # [W,H]
-                    alpha_mask = transforms.ToTensor()(alpha_mask)
+                        alpha_mask = torch.ones((img.shape[0], img.shape[1]), dtype=torch.float32)
                 else:
                     alpha_mask = None
+
                 img = img[:, :, :3]  # remove alpha channel
 
                 latents = None
                 image = self.image_transforms(img)  # -1.0~1.0のtorch.Tensorになる
+                del img
 
             images.append(image)
             latents_list.append(latents)
@@ -1361,6 +1364,23 @@ class BaseDataset(torch.utils.data.Dataset):
             example["text_encoder_outputs2_list"] = torch.stack(text_encoder_outputs2_list)
             example["text_encoder_pool2_list"] = torch.stack(text_encoder_pool2_list)
 
+        # if one of alpha_masks is not None, we need to replace None with ones
+        none_or_not = [x is None for x in alpha_mask_list]
+        if all(none_or_not):
+            example["alpha_masks"] = None
+        elif any(none_or_not):
+            for i in range(len(alpha_mask_list)):
+                if alpha_mask_list[i] is None:
+                    if images[i] is not None:
+                        alpha_mask_list[i] = torch.ones((images[i].shape[1], images[i].shape[2]), dtype=torch.float32)
+                    else:
+                        alpha_mask_list[i] = torch.ones(
+                            (latents_list[i].shape[1] * 8, latents_list[i].shape[2] * 8), dtype=torch.float32
+                        )
+            example["alpha_masks"] = torch.stack(alpha_mask_list)
+        else:
+            example["alpha_masks"] = torch.stack(alpha_mask_list)
+
         if images[0] is not None:
             images = torch.stack(images)
             images = images.to(memory_format=torch.contiguous_format).float()
@@ -1378,8 +1398,6 @@ class BaseDataset(torch.utils.data.Dataset):
 
         example["network_multipliers"] = torch.FloatTensor([self.network_multiplier] * len(captions))
 
-        example["alpha_mask"] = torch.stack(alpha_mask_list) if alpha_mask_list[0] is not None else None
-
         if self.debug_dataset:
             example["image_keys"] = bucket[image_index : image_index + self.batch_size]
         return example
@@ -1393,6 +1411,7 @@ class BaseDataset(torch.utils.data.Dataset):
         resized_sizes = []
         bucket_reso = None
         flip_aug = None
+        alpha_mask = None
         random_crop = None
 
         for image_key in bucket[image_index : image_index + bucket_batch_size]:
@@ -1401,10 +1420,13 @@ class BaseDataset(torch.utils.data.Dataset):
 
             if flip_aug is None:
                 flip_aug = subset.flip_aug
+                alpha_mask = subset.alpha_mask
                 random_crop = subset.random_crop
                 bucket_reso = image_info.bucket_reso
             else:
+                # TODO そもそも混在してても動くようにしたほうがいい
                 assert flip_aug == subset.flip_aug, "flip_aug must be same in a batch"
+                assert alpha_mask == subset.alpha_mask, "alpha_mask must be same in a batch"
                 assert random_crop == subset.random_crop, "random_crop must be same in a batch"
                 assert bucket_reso == image_info.bucket_reso, "bucket_reso must be same in a batch"
 
@@ -1441,6 +1463,7 @@ class BaseDataset(torch.utils.data.Dataset):
         example["absolute_paths"] = absolute_paths
         example["resized_sizes"] = resized_sizes
         example["flip_aug"] = flip_aug
+        example["alpha_mask"] = alpha_mask
         example["random_crop"] = random_crop
         example["bucket_reso"] = bucket_reso
         return example
@@ -2149,7 +2172,7 @@ class DatasetGroup(torch.utils.data.ConcatDataset):
             dataset.disable_token_padding()
 
 
-def is_disk_cached_latents_is_expected(reso, npz_path: str, flip_aug: bool):
+def is_disk_cached_latents_is_expected(reso, npz_path: str, flip_aug: bool, alpha_mask: bool):
     expected_latents_size = (reso[1] // 8, reso[0] // 8)  # bucket_resoはWxHなので注意
 
     if not os.path.exists(npz_path):
@@ -2167,6 +2190,12 @@ def is_disk_cached_latents_is_expected(reso, npz_path: str, flip_aug: bool):
                 return False
             if npz["latents_flipped"].shape[1:3] != expected_latents_size:
                 return False
+
+        if alpha_mask:
+            if "alpha_mask" not in npz:
+                return False
+            if npz["alpha_mask"].shape[0:2] != reso:  # HxW
+                return False
     except Exception as e:
         logger.error(f"Error loading file: {npz_path}")
         raise e
@@ -2177,14 +2206,7 @@ def is_disk_cached_latents_is_expected(reso, npz_path: str, flip_aug: bool):
 # 戻り値は、latents_tensor, (original_size width, original_size height), (crop left, crop top)
 def load_latents_from_disk(
     npz_path,
-) -> Tuple[
-    Optional[torch.Tensor],
-    Optional[List[int]],
-    Optional[List[int]],
-    Optional[torch.Tensor],
-    Optional[torch.Tensor],
-    Optional[torch.Tensor],
-]:
+) -> Tuple[Optional[torch.Tensor], Optional[List[int]], Optional[List[int]], Optional[np.ndarray], Optional[np.ndarray]]:
     npz = np.load(npz_path)
     if "latents" not in npz:
         raise ValueError(f"error: npz is old format. please re-generate {npz_path}")
@@ -2194,20 +2216,15 @@ def load_latents_from_disk(
     crop_ltrb = npz["crop_ltrb"].tolist()
     flipped_latents = npz["latents_flipped"] if "latents_flipped" in npz else None
     alpha_mask = npz["alpha_mask"] if "alpha_mask" in npz else None
-    flipped_alpha_mask = npz["flipped_alpha_mask"] if "flipped_alpha_mask" in npz else None
-    return latents, original_size, crop_ltrb, flipped_latents, alpha_mask, flipped_alpha_mask
+    return latents, original_size, crop_ltrb, flipped_latents, alpha_mask
 
 
-def save_latents_to_disk(
-    npz_path, latents_tensor, original_size, crop_ltrb, flipped_latents_tensor=None, alpha_mask=None, flipped_alpha_mask=None
-):
+def save_latents_to_disk(npz_path, latents_tensor, original_size, crop_ltrb, flipped_latents_tensor=None, alpha_mask=None):
     kwargs = {}
     if flipped_latents_tensor is not None:
         kwargs["latents_flipped"] = flipped_latents_tensor.float().cpu().numpy()
     if alpha_mask is not None:
-        kwargs["alpha_mask"] = alpha_mask.float().cpu().numpy()
-    if flipped_alpha_mask is not None:
-        kwargs["flipped_alpha_mask"] = flipped_alpha_mask.float().cpu().numpy()
+        kwargs["alpha_mask"] = alpha_mask  # ndarray
     np.savez(
         npz_path,
         latents=latents_tensor.float().cpu().numpy(),
@@ -2398,10 +2415,11 @@ def load_arbitrary_dataset(args, tokenizer) -> MinimalDataset:
 
 def load_image(image_path, alpha=False):
     image = Image.open(image_path)
-    if not image.mode == "RGB":
-        if alpha:
+    if alpha:
+        if not image.mode == "RGBA":
             image = image.convert("RGBA")
-        else:
+    else:
+        if not image.mode == "RGB":
             image = image.convert("RGB")
     img = np.array(image, np.uint8)
     return img
@@ -2441,7 +2459,7 @@ def trim_and_resize_if_required(
 
 
 def cache_batch_latents(
-    vae: AutoencoderKL, cache_to_disk: bool, image_infos: List[ImageInfo], flip_aug: bool, random_crop: bool
+    vae: AutoencoderKL, cache_to_disk: bool, image_infos: List[ImageInfo], flip_aug: bool, use_alpha_mask: bool, random_crop: bool
 ) -> None:
     r"""
     requires image_infos to have: absolute_path, bucket_reso, resized_size, latents_npz
@@ -2453,49 +2471,43 @@ def cache_batch_latents(
     latents_original_size and latents_crop_ltrb are also set
     """
     images = []
-    alpha_masks = []
+    alpha_masks: List[np.ndarray] = []
     for info in image_infos:
-        image = load_image(info.absolute_path, info.use_alpha_mask) if info.image is None else np.array(info.image, np.uint8)
+        image = load_image(info.absolute_path, use_alpha_mask) if info.image is None else np.array(info.image, np.uint8)
         # TODO 画像のメタデータが壊れていて、メタデータから割り当てたbucketと実際の画像サイズが一致しない場合があるのでチェック追加要
         image, original_size, crop_ltrb = trim_and_resize_if_required(random_crop, image, info.bucket_reso, info.resized_size)
-        if info.use_alpha_mask:
-            if image.shape[2] == 4:
-                alpha_mask = image[:, :, 3]  # [W,H]
-                image = image[:, :, :3]
-            else:
-                alpha_mask = np.full_like(image[:, :, 0], 255, dtype=np.uint8)  # [W,H]
-            alpha_masks.append(transforms.ToTensor()(alpha_mask))
-        image = IMAGE_TRANSFORMS(image)
-        images.append(image)
 
         info.latents_original_size = original_size
         info.latents_crop_ltrb = crop_ltrb
 
+        if use_alpha_mask:
+            if image.shape[2] == 4:
+                alpha_mask = image[:, :, 3]  # [H,W]
+                alpha_mask = alpha_mask.astype(np.float32) / 255.0
+            else:
+                alpha_mask = np.ones_like(image[:, :, 0], dtype=np.float32)
+        else:
+            alpha_mask = None
+        alpha_masks.append(alpha_mask)
+
+        image = image[:, :, :3]  # remove alpha channel if exists
+        image = IMAGE_TRANSFORMS(image)
+        images.append(image)
+
     img_tensors = torch.stack(images, dim=0)
     img_tensors = img_tensors.to(device=vae.device, dtype=vae.dtype)
 
     with torch.no_grad():
         latents = vae.encode(img_tensors).latent_dist.sample().to("cpu")
 
-    if info.use_alpha_mask:
-        alpha_masks = torch.stack(alpha_masks, dim=0).to("cpu")
-    else:
-        alpha_masks = [None] * len(image_infos)
-        flipped_alpha_masks = [None] * len(image_infos)
-
     if flip_aug:
         img_tensors = torch.flip(img_tensors, dims=[3])
         with torch.no_grad():
             flipped_latents = vae.encode(img_tensors).latent_dist.sample().to("cpu")
-        if info.use_alpha_mask:
-            flipped_alpha_masks = torch.flip(alpha_masks, dims=[3])
     else:
         flipped_latents = [None] * len(latents)
-        flipped_alpha_masks = [None] * len(image_infos)
 
-    for info, latent, flipped_latent, alpha_mask, flipped_alpha_mask in zip(
-        image_infos, latents, flipped_latents, alpha_masks, flipped_alpha_masks
-    ):
+    for info, latent, flipped_latent, alpha_mask in zip(image_infos, latents, flipped_latents, alpha_masks):
         # check NaN
         if torch.isnan(latents).any() or (flipped_latent is not None and torch.isnan(flipped_latent).any()):
             raise RuntimeError(f"NaN detected in latents: {info.absolute_path}")
@@ -2508,15 +2520,12 @@ def cache_batch_latents(
                 info.latents_crop_ltrb,
                 flipped_latent,
                 alpha_mask,
-                flipped_alpha_mask,
             )
         else:
             info.latents = latent
             if flip_aug:
                 info.latents_flipped = flipped_latent
-
             info.alpha_mask = alpha_mask
-            info.alpha_mask_flipped = flipped_alpha_mask
 
     if not HIGH_VRAM:
         clean_memory_on_device(vae.device)
diff --git a/sdxl_train.py b/sdxl_train.py
index dcd06766..9e20c60c 100644
--- a/sdxl_train.py
+++ b/sdxl_train.py
@@ -711,10 +711,8 @@ def train(args):
                     loss = train_util.conditional_loss(
                         noise_pred.float(), target.float(), reduction="none", loss_type=args.loss_type, huber_c=huber_c
                     )
-                    if args.masked_loss:
-                        loss = apply_masked_loss(loss, batch["conditioning_images"][:, 0].unsqueeze(1))
-                    if "alpha_mask" in batch and batch["alpha_mask"] is not None:
-                        loss = apply_masked_loss(loss, batch["alpha_mask"])
+                    if args.masked_loss or ("alpha_masks" in batch and batch["alpha_masks"] is not None):
+                        loss = apply_masked_loss(loss, batch)
                     loss = loss.mean([1, 2, 3])
 
                     if args.min_snr_gamma:
diff --git a/tools/cache_latents.py b/tools/cache_latents.py
index 347db27f..b7c88121 100644
--- a/tools/cache_latents.py
+++ b/tools/cache_latents.py
@@ -17,10 +17,13 @@ from library.config_util import (
     BlueprintGenerator,
 )
 from library.utils import setup_logging
+
 setup_logging()
 import logging
+
 logger = logging.getLogger(__name__)
 
+
 def cache_to_disk(args: argparse.Namespace) -> None:
     train_util.prepare_dataset_args(args, True)
 
@@ -107,7 +110,7 @@ def cache_to_disk(args: argparse.Namespace) -> None:
     else:
         _, vae, _, _ = train_util.load_target_model(args, weight_dtype, accelerator)
 
-    if torch.__version__ >= "2.0.0": # PyTorch 2.0.0 以上対応のxformersなら以下が使える
+    if torch.__version__ >= "2.0.0":  # PyTorch 2.0.0 以上対応のxformersなら以下が使える
         vae.set_use_memory_efficient_attention_xformers(args.xformers)
     vae.to(accelerator.device, dtype=vae_dtype)
     vae.requires_grad_(False)
@@ -136,6 +139,7 @@ def cache_to_disk(args: argparse.Namespace) -> None:
         b_size = len(batch["images"])
         vae_batch_size = b_size if args.vae_batch_size is None else args.vae_batch_size
         flip_aug = batch["flip_aug"]
+        alpha_mask = batch["alpha_mask"]
         random_crop = batch["random_crop"]
         bucket_reso = batch["bucket_reso"]
 
@@ -154,14 +158,16 @@ def cache_to_disk(args: argparse.Namespace) -> None:
                 image_info.latents_npz = os.path.splitext(absolute_path)[0] + ".npz"
 
                 if args.skip_existing:
-                    if train_util.is_disk_cached_latents_is_expected(image_info.bucket_reso, image_info.latents_npz, flip_aug):
+                    if train_util.is_disk_cached_latents_is_expected(
+                        image_info.bucket_reso, image_info.latents_npz, flip_aug, alpha_mask
+                    ):
                         logger.warning(f"Skipping {image_info.latents_npz} because it already exists.")
                         continue
 
                 image_infos.append(image_info)
 
             if len(image_infos) > 0:
-                train_util.cache_batch_latents(vae, True, image_infos, flip_aug, random_crop)
+                train_util.cache_batch_latents(vae, True, image_infos, flip_aug, alpha_mask, random_crop)
 
     accelerator.wait_for_everyone()
     accelerator.print(f"Finished caching latents for {len(train_dataset_group)} batches.")
diff --git a/train_db.py b/train_db.py
index c4690000..39d8ea6e 100644
--- a/train_db.py
+++ b/train_db.py
@@ -359,10 +359,8 @@ def train(args):
                     target = noise
 
                 loss = train_util.conditional_loss(noise_pred.float(), target.float(), reduction="none", loss_type=args.loss_type, huber_c=huber_c)
-                if args.masked_loss:
-                    loss = apply_masked_loss(loss, batch["conditioning_images"][:, 0].unsqueeze(1))
-                if "alpha_mask" in batch and batch["alpha_mask"] is not None:
-                    loss = apply_masked_loss(loss, batch["alpha_mask"])
+                if args.masked_loss or ("alpha_masks" in batch and batch["alpha_masks"] is not None):
+                    loss = apply_masked_loss(loss, batch)
                 loss = loss.mean([1, 2, 3])
 
                 loss_weights = batch["loss_weights"]  # 各sampleごとのweight
diff --git a/train_network.py b/train_network.py
index cd1677ad..b272a6e1 100644
--- a/train_network.py
+++ b/train_network.py
@@ -774,7 +774,9 @@ class NetworkTrainer:
             if args.log_tracker_config is not None:
                 init_kwargs = toml.load(args.log_tracker_config)
             accelerator.init_trackers(
-                "network_train" if args.log_tracker_name is None else args.log_tracker_name, config=train_util.get_sanitized_config_or_none(args), init_kwargs=init_kwargs
+                "network_train" if args.log_tracker_name is None else args.log_tracker_name,
+                config=train_util.get_sanitized_config_or_none(args),
+                init_kwargs=init_kwargs,
             )
 
         loss_recorder = train_util.LossRecorder()
@@ -902,10 +904,8 @@ class NetworkTrainer:
                     loss = train_util.conditional_loss(
                         noise_pred.float(), target.float(), reduction="none", loss_type=args.loss_type, huber_c=huber_c
                     )
-                    if args.masked_loss:
-                        loss = apply_masked_loss(loss, batch["conditioning_images"][:, 0].unsqueeze(1))
-                    if "alpha_mask" in batch and batch["alpha_mask"] is not None:
-                        loss = apply_masked_loss(loss, batch["alpha_mask"])
+                    if args.masked_loss or ("alpha_masks" in batch and batch["alpha_masks"] is not None):
+                        loss = apply_masked_loss(loss, batch)
                     loss = loss.mean([1, 2, 3])
 
                     loss_weights = batch["loss_weights"]  # 各sampleごとのweight
diff --git a/train_textual_inversion.py b/train_textual_inversion.py
index a9c2a109..ade077c3 100644
--- a/train_textual_inversion.py
+++ b/train_textual_inversion.py
@@ -589,10 +589,8 @@ class TextualInversionTrainer:
                         target = noise
 
                     loss = train_util.conditional_loss(noise_pred.float(), target.float(), reduction="none", loss_type=args.loss_type, huber_c=huber_c)
-                    if args.masked_loss:
-                        loss = apply_masked_loss(loss, batch["conditioning_images"][:, 0].unsqueeze(1))
-                    if "alpha_mask" in batch and batch["alpha_mask"] is not None:
-                        loss = apply_masked_loss(loss, batch["alpha_mask"])
+                    if args.masked_loss or ("alpha_masks" in batch and batch["alpha_masks"] is not None):
+                        loss = apply_masked_loss(loss, batch)
                     loss = loss.mean([1, 2, 3])
 
                     loss_weights = batch["loss_weights"]  # 各sampleごとのweight
diff --git a/train_textual_inversion_XTI.py b/train_textual_inversion_XTI.py
index 959839cb..efb59137 100644
--- a/train_textual_inversion_XTI.py
+++ b/train_textual_inversion_XTI.py
@@ -474,10 +474,8 @@ def train(args):
                     target = noise
 
                 loss = train_util.conditional_loss(noise_pred.float(), target.float(), reduction="none", loss_type=args.loss_type, huber_c=huber_c)
-                if args.masked_loss:
-                    loss = apply_masked_loss(loss, batch["conditioning_images"][:, 0].unsqueeze(1))
-                if "alpha_mask" in batch and batch["alpha_mask"] is not None:
-                    loss = apply_masked_loss(loss, batch["alpha_mask"])
+                if args.masked_loss or ("alpha_masks" in batch and batch["alpha_masks"] is not None):
+                    loss = apply_masked_loss(loss, batch)
                 loss = loss.mean([1, 2, 3])
 
                 loss_weights = batch["loss_weights"]  # 各sampleごとのweight