diff --git a/CHANGELOG_CHERRYPICK.md b/CHANGELOG_CHERRYPICK.md
index 59cea6ce3e..e2e7136835 100644
--- a/CHANGELOG_CHERRYPICK.md
+++ b/CHANGELOG_CHERRYPICK.md
@@ -45,6 +45,9 @@ Misskey의 전체 변경 사항을 확인하려면, [CHANGELOG.md#2024xx](CHANGE
 - Feat: 답글 대상 노트의 반투명 옵션을 선택할 수 있음 (kokonect-link/cherrypick#495)
 - Feat: 사용자 페이지의 미디어 탭을 그리드 레이아웃으로 설정할 수 있음 (kokonect-link/cherrypick#494)
 - Feat: 검색 위젯 (1673beta/cherrypick#125)
+- Feat: 캡션 미설정 안내 표시 (1673beta/cherrypick#142)
+  - 노트를 게시하기 전에 첨부한 파일에 캡션이 없으면 경고를 표시합니다.
+  - 이 변경으로 이미지 뷰어의 파일 이름 영역에는 더 이상 캡션이 아닌 실제 파일 이름이 표시됩니다.
 
 ### Client
 - Enhance: CherryPick 업데이트 페이지를 제어판 목록에 추가함
@@ -55,7 +58,13 @@ Misskey의 전체 변경 사항을 확인하려면, [CHANGELOG.md#2024xx](CHANGE
 - Enhance: 설정 페이지 개선
   - 일반 설정에 있던 설정 중 디자인과 관련된 설정을 모양으로 옮겼습니다.
 - Enhance: 외부 사이트로 이동할 때 경고 표시 (MisskeyIO/misskey#558)
+- Enhance: 이미지의 확장자를 더욱 정확하게 표시함
+  - APNG 형식의 이미지가 GIF로 표시되던 것을 APNG로 표시하도록 변경
+- Enhance: 이미지 뷰어가 파일 이름과 캡션을 동시에 표시하도록 변경
+- Enhance: 노트를 작성할 때 첨부한 파일에 캡션이 존재하는 경우 파일 목록에 아이콘을 표시함
+- Enhance: 미디어 숨기기 버튼의 디자인을 개선함
 - Fix: 환경설정 백업 시 일부 설정이 누락되어 백업될 수 있음
+- Fix: 이미지 자르기를 할 때 이미지 크기 전체를 표시하지 못할 수 있음
 
 ---
 
diff --git a/locales/en-US.yml b/locales/en-US.yml
index 865c2e2f9d..f839aebbb1 100644
--- a/locales/en-US.yml
+++ b/locales/en-US.yml
@@ -1,5 +1,7 @@
 ---
 _lang_: "English"
+showNoAltWarning: "Show caption unset warning"
+showNoAltWarningDescription: "Display a warning when no alternate text is set in the image"
 filesGridLayoutInUserPage: "Change the media tab to grid layout"
 filesGridLayoutInUserPageDescription: "When this function is turned on, the Media tab on your page is shown in album format.\nTurning it off will change to the original note timeline."
 showReplyTargetNoteInSemiTransparent: "Show reply target note in semi-transparent"
@@ -1479,8 +1481,8 @@ _cherrypick:
   reactableRemoteReaction: "Allow remote custom emoji reactions to react if there is an emoji with the same name on this server."
   showFollowingMessageInsteadOfButton: "Do not show the follow button in the notification field if you are already following someone"
   mobileHeaderChange: "Header design change in mobile environment"
-  renameTheButtonInPostFormToNya: "Change the \"Note\" button on the note-posting form to \"Nyan!\""
-  renameTheButtonInPostFormToNyaDescription: "Outside of the note-posting form, they are still as \"Note\"."
+  renameTheButtonInPostFormToNya: "Change the \"Note\" button on the posting form to \"Nyan!\""
+  renameTheButtonInPostFormToNyaDescription: "Outside of the posting form, they are still as \"Note\"."
   enableWidgetsArea: "Enable the widgets area"
   disableWidgetsArea: "Disable the widgets area"
   friendlyUiEnableNotificationsArea: "Enable the notifications area"
@@ -3016,3 +3018,6 @@ _externalNavigationWarning:
   title: "Navigate to an external site"
   description: "Leave {host} and go to an external site"
   trustThisDomain: "Trust this domain on this device in the future"
+_altWarning:
+  noAltWarning: "No alternate text is configured in the file."
+  noAltWarningDescription: "You can change this setting in \"Settings - Appearance\"."
diff --git a/locales/index.d.ts b/locales/index.d.ts
index 898113106b..1692fc7142 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -13,6 +13,14 @@ export interface Locale extends ILocale {
      * 日本語
      */
     "_lang_": string;
+    /**
+     * キャプション未設定案内を表示
+     */
+    "showNoAltWarning": string;
+    /**
+     * 画像に代替テキストが設定されていない場合に警告を表示する
+     */
+    "showNoAltWarningDescription": string;
     /**
      * メディアタブをグリッドレイアウトに変更
      */
@@ -11794,6 +11802,16 @@ export interface Locale extends ILocale {
          */
         "trustThisDomain": string;
     };
+    "_altWarning": {
+        /**
+         * ファイルに代替テキストが設定されていません。
+         */
+        "noAltWarning": string;
+        /**
+         * この設定は「設定 - アピアランス」で変更できます。
+         */
+        "noAltWarningDescription": string;
+    };
 }
 declare const locales: {
     [lang: string]: Locale;
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 53942940ed..cc0c9072d3 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -1,5 +1,7 @@
 _lang_: "日本語"
 
+showNoAltWarning: "キャプション未設定案内を表示"
+showNoAltWarningDescription: "画像に代替テキストが設定されていない場合に警告を表示する"
 filesGridLayoutInUserPage: "メディアタブをグリッドレイアウトに変更"
 filesGridLayoutInUserPageDescription: "この設定をオンにすると、ユーザーページのメディアタブがアルバム形式で表示されます。\nオフにすると、元のノートのタイムラインに変更されます。"
 showReplyTargetNoteInSemiTransparent: "返信対象ノートを半透明に表示"
@@ -3140,3 +3142,7 @@ _externalNavigationWarning:
   title: "外部サイトに移動します"
   description: "{host}を離れて外部サイトに移動します"
   trustThisDomain: "このデバイスで今後このドメインを信頼する"
+
+_altWarning:
+  noAltWarning: "ファイルに代替テキストが設定されていません。"
+  noAltWarningDescription: "この設定は「設定 - アピアランス」で変更できます。"
diff --git a/locales/ko-KR.yml b/locales/ko-KR.yml
index bb71c1379c..044c327a11 100644
--- a/locales/ko-KR.yml
+++ b/locales/ko-KR.yml
@@ -1,5 +1,7 @@
 ---
 _lang_: "한국어"
+showNoAltWarning: "캡션 미설정 안내 표시"
+showNoAltWarningDescription: "이미지에 캡션이 설정되어 있지 않으면 경고를 표시해요"
 filesGridLayoutInUserPage: "미디어 탭을 그리드 레이아웃으로 변경"
 filesGridLayoutInUserPageDescription: "이 설정을 켜면 사용자 페이지의 미디어 탭이 앨범 형식으로 보여져요.\n끄면 원래의 노트 타임라인으로 변경돼요."
 showReplyTargetNoteInSemiTransparent: "답글 대상 노트를 반투명하게 표시"
@@ -3047,3 +3049,6 @@ _externalNavigationWarning:
   title: "외부 사이트로 이동할까요?"
   description: "{host}을(를) 떠나 외부 사이트로 이동하려고 해요"
   trustThisDomain: "이 장치에서 앞으로 이 도메인을 신뢰할게요"
+_altWarning:
+  noAltWarning: "파일에 캡션이 설정되어 있지 않아요."
+  noAltWarningDescription: "이 설정은 [설정 - 모양]에서 변경할 수 있어요."
diff --git a/packages/frontend/src/components/MkCropperDialog.vue b/packages/frontend/src/components/MkCropperDialog.vue
index 4f490510c1..8c74fa1735 100644
--- a/packages/frontend/src/components/MkCropperDialog.vue
+++ b/packages/frontend/src/components/MkCropperDialog.vue
@@ -113,6 +113,7 @@ const onImageLoad = () => {
 	loading.value = false;
 
 	if (cropper) {
+		cropper.getCropperCanvas();
 		cropper.getCropperImage()!.$center('contain');
 		cropper.getCropperSelection()!.$center();
 	}
@@ -159,6 +160,7 @@ onMounted(() => {
 	width: var(--vw);
 	height: var(--vh);
 	position: relative;
+	object-fit: contain;
 
 	> .loading {
 		position: absolute;
@@ -183,6 +185,7 @@ onMounted(() => {
 		> ::v-deep(cropper-canvas) {
 			width: 100%;
 			height: 100%;
+			object-fit: contain;
 
 			> cropper-selection > cropper-handle[action="move"] {
 				background: transparent;
diff --git a/packages/frontend/src/components/MkDriveFileThumbnail.vue b/packages/frontend/src/components/MkDriveFileThumbnail.vue
index d20e660788..20475e69e8 100644
--- a/packages/frontend/src/components/MkDriveFileThumbnail.vue
+++ b/packages/frontend/src/components/MkDriveFileThumbnail.vue
@@ -11,7 +11,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 		{ [$style.sensitiveHighlight]: highlightWhenSensitive && file.isSensitive },
 	]"
 >
-	<ImgWithBlurhash v-if="isThumbnailAvailable" :hash="file.blurhash" :src="file.thumbnailUrl" :alt="file.name" :title="file.name" :cover="fit !== 'contain'"/>
+	<ImgWithBlurhash v-if="isThumbnailAvailable" :hash="file.blurhash" :src="file.thumbnailUrl" :alt="file.comment" :title="file.name" :cover="fit !== 'contain'" :showAltIndicator="showAltIndicator"/>
 	<i v-else-if="is === 'image'" class="ti ti-photo" :class="$style.icon"></i>
 	<i v-else-if="is === 'video'" class="ti ti-video" :class="$style.icon"></i>
 	<i v-else-if="is === 'audio' || is === 'midi'" class="ti ti-file-music" :class="$style.icon"></i>
@@ -34,6 +34,7 @@ const props = defineProps<{
 	file: Misskey.entities.DriveFile;
 	fit: 'cover' | 'contain';
 	highlightWhenSensitive?: boolean;
+	showAltIndicator?: boolean;
 }>();
 
 const is = computed(() => {
diff --git a/packages/frontend/src/components/MkImgWithBlurhash.vue b/packages/frontend/src/components/MkImgWithBlurhash.vue
index 837a9e17ae..a1794fab13 100644
--- a/packages/frontend/src/components/MkImgWithBlurhash.vue
+++ b/packages/frontend/src/components/MkImgWithBlurhash.vue
@@ -16,6 +16,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	>
 		<canvas v-show="hide" key="canvas" ref="canvas" :class="$style.canvas" :width="canvasWidth" :height="canvasHeight" :title="title ?? undefined" tabindex="-1"/>
 		<img v-show="!hide" key="img" ref="img" :height="imgHeight ?? undefined" :width="imgWidth ?? undefined" :class="[$style.img, { [$style.noDrag]: noDrag }]" :src="src ?? undefined" :title="title ?? undefined" :alt="alt ?? undefined" loading="eager" decoding="async" tabindex="-1"/>
+		<i v-if="alt && showAltIndicator" :class="$style.altIndicator" class="ti ti-alt"></i>
 	</TransitionGroup>
 </div>
 </template>
@@ -82,6 +83,7 @@ const props = withDefaults(defineProps<{
 	forceBlurhash?: boolean;
 	onlyAvgColor?: boolean; // 軽量化のためにBlurhashを使わずに平均色だけを描画
 	noDrag?: boolean;
+	showAltIndicator?: boolean;
 }>(), {
 	transition: null,
 	src: null,
@@ -93,6 +95,7 @@ const props = withDefaults(defineProps<{
 	forceBlurhash: false,
 	onlyAvgColor: false,
 	noDrag: false,
+	showAltIndicator: false,
 });
 
 const viewId = uuid();
@@ -269,4 +272,21 @@ onUnmounted(() => {
 		-webkit-user-drag: none;
 	}
 }
+
+.altIndicator {
+	display: flex;
+	gap: 4px;
+	position: absolute;
+	border-radius: 8px;
+	overflow: hidden;
+	top: 2.5px;
+	right: 2px;
+	background-color: var(--bg);
+	-webkit-backdrop-filter: var(--blur, blur(15px));
+	backdrop-filter: var(--blur, blur(15px));
+	color: var(--accent);
+	font-size: 1em;
+	padding: 2px 4px;
+	text-align: center;
+}
 </style>
diff --git a/packages/frontend/src/components/MkMediaImage.vue b/packages/frontend/src/components/MkMediaImage.vue
index bae422cd1c..43456cae1d 100644
--- a/packages/frontend/src/components/MkMediaImage.vue
+++ b/packages/frontend/src/components/MkMediaImage.vue
@@ -23,7 +23,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			:forceBlurhash="hide"
 			:cover="hide || cover"
 			:alt="image.comment || image.name"
-			:title="image.comment || image.name"
+			:title="image.name"
 			:width="image.properties.width"
 			:height="image.properties.height"
 			:style="hide ? 'filter: brightness(0.7);' : null"
@@ -44,7 +44,8 @@ SPDX-License-Identifier: AGPL-3.0-only
 	</template>
 	<template v-else-if="controls">
 		<div :class="$style.indicators">
-			<div v-if="['image/gif', 'image/apng'].includes(image.type)" :class="$style.indicator">GIF</div>
+			<div v-if="['image/gif'].includes(image.type)" :class="$style.indicator">GIF</div>
+			<div v-if="['image/apng'].includes(image.type)" :class="$style.indicator">APNG</div>
 			<div v-if="image.comment" :class="$style.indicator">ALT</div>
 			<div v-if="image.isSensitive" :class="$style.indicator" style="color: var(--warn);" :title="i18n.ts.sensitive"><i class="ti ti-eye-exclamation"></i></div>
 		</div>
@@ -232,10 +233,10 @@ onUnmounted(() => {
 	display: block;
 	position: absolute;
 	border-radius: 6px;
-	background-color: var(--fg);
+	background-color: var(--bg);
 	color: var(--accentLighten);
-	font-size: 12px;
-	opacity: .5;
+	font-size: 18px;
+	opacity: .7;
 	padding: 5px 8px;
 	text-align: center;
 	cursor: pointer;
diff --git a/packages/frontend/src/components/MkMediaList.vue b/packages/frontend/src/components/MkMediaList.vue
index 44dd31cd6a..8c72f74df9 100644
--- a/packages/frontend/src/components/MkMediaList.vue
+++ b/packages/frontend/src/components/MkMediaList.vue
@@ -153,8 +153,9 @@ onMounted(() => {
 			[itemData.w, itemData.h] = [itemData.h, itemData.w];
 		}
 		itemData.msrc = file.thumbnailUrl ?? undefined;
-		itemData.alt = file.comment ?? file.name;
+		itemData.alt = file.comment ?? undefined;
 		itemData.comment = file.comment ?? file.name;
+		itemData.title = file.name;
 		itemData.thumbCropped = true;
 
 		return itemData;
@@ -180,6 +181,25 @@ onMounted(() => {
 
 				pswp.on('change', () => {
 					textBox.textContent = pswp.currSlide?.data.comment;
+
+					const altText = pswp.currSlide?.data.alt || null;
+					textBox.textContent = altText;
+					if (!altText) {
+						el.style.display = 'none';
+					}
+				});
+			},
+		});
+		lightbox?.pswp?.ui?.registerElement({
+			name: 'fileName',
+			className: 'pswp__file-name-container',
+			appendTo: 'wrapper',
+			onInit: (el, pswp) => {
+				const textBox = document.createElement('p');
+				textBox.className = 'pswp__file-name _acrylic';
+				el.appendChild(textBox);
+				pswp.on('change', () => {
+					textBox.textContent = pswp.currSlide?.data.title;
 				});
 			},
 		});
@@ -339,12 +359,20 @@ defineExpose({
 	align-items: center;
 
 	position: absolute;
-	bottom: 20px;
+	bottom: 100px;
 	left: 50%;
 	transform: translateX(-50%);
 
 	width: 75%;
 	max-width: 800px;
+
+	z-index: 2;
+}
+
+.pswp__file-name-container {
+	@extend .pswp__alt-text-container;
+	bottom: 20px;
+	z-index: 1;
 }
 
 .pswp__alt-text {
@@ -358,4 +386,9 @@ defineExpose({
 	text-shadow: var(--bg) 0 0 10px, var(--bg) 0 0 3px, var(--bg) 0 0 3px;
 	white-space: pre-line;
 }
+
+.pswp__file-name {
+	@extend .pswp__alt-text;
+	max-height: 16em;
+}
 </style>
diff --git a/packages/frontend/src/components/MkPostForm.vue b/packages/frontend/src/components/MkPostForm.vue
index faf0ab6620..c7d22c6d8a 100644
--- a/packages/frontend/src/components/MkPostForm.vue
+++ b/packages/frontend/src/components/MkPostForm.vue
@@ -186,7 +186,7 @@ const visibilityButton = shallowRef<HTMLElement>();
 const posting = ref(false);
 const posted = ref(false);
 const text = ref(props.initialText ?? '');
-const files = ref(props.initialFiles ?? []);
+const files = ref(props.initialFiles ?? ([] as Misskey.entities.DriveFile[]));
 const poll = ref<PollEditorModelValue | null>(null);
 const event = ref<{
 	title: string;
@@ -785,6 +785,17 @@ async function post(ev?: MouseEvent) {
 		return;
 	}
 
+	if (defaultStore.state.showNoAltTextWarning && files.value.some((f) => f.comment == null || f.comment.length === 0)) {
+		const { canceled } = await os.confirm({
+			type: 'warning',
+			text: i18n.ts._altWarning.noAltWarning,
+			caption: i18n.ts._altWarning.noAltWarningDescription,
+			okText: i18n.ts.goBack,
+			cancelText: i18n.ts.thisPostMayBeAnnoyingIgnore,
+		});
+		if (!canceled) return;
+	}
+
 	if (ev) {
 		const el = (ev.currentTarget ?? ev.target) as HTMLElement | null;
 
diff --git a/packages/frontend/src/components/MkPostFormAttaches.vue b/packages/frontend/src/components/MkPostFormAttaches.vue
index bf2423762d..bd5793349a 100644
--- a/packages/frontend/src/components/MkPostFormAttaches.vue
+++ b/packages/frontend/src/components/MkPostFormAttaches.vue
@@ -8,7 +8,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	<Sortable :modelValue="props.modelValue" :class="$style.files" itemKey="id" :animation="150" :delay="100" :delayOnTouchOnly="true" @update:modelValue="v => emit('update:modelValue', v)">
 		<template #item="{element}">
 			<div :class="$style.file" @click="showFileMenu(element, $event)" @contextmenu.prevent="showFileMenu(element, $event)">
-				<MkDriveFileThumbnail :data-id="element.id" :class="$style.thumbnail" :file="element" fit="cover"/>
+				<MkDriveFileThumbnail :data-id="element.id" :class="$style.thumbnail" :file="element" fit="cover" :showAltIndicator="true"/>
 				<div v-if="element.isSensitive" :class="$style.sensitive">
 					<i class="ti ti-eye-exclamation" style="margin: auto;"></i>
 				</div>
diff --git a/packages/frontend/src/components/MkPostFormSimple.vue b/packages/frontend/src/components/MkPostFormSimple.vue
index 7f05f6849f..5d6fa7113b 100644
--- a/packages/frontend/src/components/MkPostFormSimple.vue
+++ b/packages/frontend/src/components/MkPostFormSimple.vue
@@ -204,7 +204,7 @@ const showForm = ref(false);
 const posting = ref(false);
 const posted = ref(false);
 const text = ref(props.initialText ?? '');
-const files = ref(props.initialFiles ?? []);
+const files = ref(props.initialFiles ?? ([] as Misskey.entities.DriveFile[]));
 const poll = ref<PollEditorModelValue | null>(null);
 const event = ref<{
 	title: string;
@@ -774,6 +774,17 @@ async function post(ev?: MouseEvent) {
 		return;
 	}
 
+	if (defaultStore.state.showNoAltTextWarning && files.value.some((f) => f.comment == null || f.comment.length === 0)) {
+		const { canceled } = await os.confirm({
+			type: 'warning',
+			text: i18n.ts._altWarning.noAltWarning,
+			caption: i18n.ts._altWarning.noAltWarningDescription,
+			okText: i18n.ts.goBack,
+			cancelText: i18n.ts.thisPostMayBeAnnoyingIgnore,
+		});
+		if (!canceled) return;
+	}
+
 	if (ev) {
 		const el = (ev.currentTarget ?? ev.target) as HTMLElement | null;
 
diff --git a/packages/frontend/src/pages/settings/appearance.vue b/packages/frontend/src/pages/settings/appearance.vue
index b70799cebb..28b936e637 100644
--- a/packages/frontend/src/pages/settings/appearance.vue
+++ b/packages/frontend/src/pages/settings/appearance.vue
@@ -180,6 +180,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 				</MkSelect>
 				<MkSwitch v-model="showFixedPostFormInReplies">{{ i18n.ts.showFixedPostFormInReplies }}<template #caption>{{ i18n.ts.showFixedPostFormInRepliesDescription }}</template> <span class="_beta">CherryPick</span></MkSwitch>
 				<MkSwitch v-model="allMediaNoteCollapse">{{ i18n.ts.allMediaNoteCollapse }} <span class="_beta">CherryPick</span></MkSwitch>
+				<MkSwitch v-model="showNoAltTextWarning">{{ i18n.ts.showNoAltWarning }}<template #caption>{{ i18n.ts.showNoAltWarningDescription }}</template> <span class="_beta">CherryPick</span></MkSwitch>
 				<MkSwitch v-model="alwaysShowCw">{{ i18n.ts.alwaysShowCw }} <span class="_beta">CherryPick</span></MkSwitch>
 				<MkSwitch v-model="showReplyTargetNoteInSemiTransparent">{{ i18n.ts.showReplyTargetNoteInSemiTransparent }} <span class="_beta">CherryPick</span></MkSwitch>
 			</div>
@@ -330,6 +331,7 @@ const renoteQuoteButtonSeparation = computed(defaultStore.makeGetterSetter('reno
 const showFixedPostFormInReplies = computed(defaultStore.makeGetterSetter('showFixedPostFormInReplies'));
 const showingAnimatedImages = computed(defaultStore.makeGetterSetter('showingAnimatedImages'));
 const allMediaNoteCollapse = computed(defaultStore.makeGetterSetter('allMediaNoteCollapse'));
+const showNoAltTextWarning = computed(defaultStore.makeGetterSetter('showNoAltTextWarning'));
 const alwaysShowCw = computed(defaultStore.makeGetterSetter('alwaysShowCw'));
 const showReplyTargetNoteInSemiTransparent = computed(defaultStore.makeGetterSetter('showReplyTargetNoteInSemiTransparent'));
 const nsfwOpenBehavior = computed(defaultStore.makeGetterSetter('nsfwOpenBehavior'));
diff --git a/packages/frontend/src/store.ts b/packages/frontend/src/store.ts
index 5a62402ef0..33b0118e45 100644
--- a/packages/frontend/src/store.ts
+++ b/packages/frontend/src/store.ts
@@ -614,6 +614,10 @@ export const defaultStore = markRaw(new Storage('base', {
 		where: 'device',
 		default: false,
 	},
+	showNoAltTextWarning: {
+		where: 'device',
+		default: true,
+	},
 	alwaysShowCw: {
 		where: 'device',
 		default: false,