diff --git a/locales/index.d.ts b/locales/index.d.ts
index 9fca2b28bc..71a341bda8 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -12083,6 +12083,10 @@ export interface Locale extends ILocale {
          * エフェクトを追加
          */
         "addEffect": string;
+        /**
+         * 変更を破棄して終了しますか？
+         */
+        "discardChangesConfirm": string;
         "_fxs": {
             /**
              * 色収差
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 9ac19aae5c..6c8414eefa 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -3237,6 +3237,7 @@ _watermarkEditor:
 _imageEffector:
   title: "エフェクト"
   addEffect: "エフェクトを追加"
+  discardChangesConfirm: "変更を破棄して終了しますか？"
 
   _fxs:
     chromaticAberration: "色収差"
diff --git a/packages/frontend/src/components/MkImageEffectorDialog.vue b/packages/frontend/src/components/MkImageEffectorDialog.vue
index 9c05e8237e..6009f82066 100644
--- a/packages/frontend/src/components/MkImageEffectorDialog.vue
+++ b/packages/frontend/src/components/MkImageEffectorDialog.vue
@@ -61,7 +61,7 @@ import { deepClone } from '@/utility/clone.js';
 import { FXS } from '@/utility/image-effector/fxs.js';
 
 const props = defineProps<{
-	image: ImageBitmap;
+	image: File;
 }>();
 
 const emit = defineEmits<{
@@ -72,7 +72,14 @@ const emit = defineEmits<{
 
 const dialog = useTemplateRef('dialog');
 
-function cancel() {
+async function cancel() {
+	if (layers.length > 0) {
+		const { canceled } = await os.confirm({
+			text: i18n.ts._imageEffector.discardChangesConfirm,
+		});
+		if (canceled) return;
+	}
+
 	emit('cancel');
 	dialog.value?.close();
 }
@@ -108,14 +115,19 @@ function onLayerDelete(layer: ImageEffectorLayer) {
 const canvasEl = useTemplateRef('canvasEl');
 
 let renderer: ImageEffector | null = null;
+let imageBitmap: ImageBitmap | null = null;
 
 onMounted(async () => {
 	if (canvasEl.value == null) return;
 
+	const closeWaiting = os.waiting();
+
+	imageBitmap = await window.createImageBitmap(props.image);
+
 	const MAX_W = 500;
 	const MAX_H = 500;
-	let w = props.image.width;
-	let h = props.image.height;
+	let w = imageBitmap.width;
+	let h = imageBitmap.height;
 
 	if (w > MAX_W || h > MAX_H) {
 		const scale = Math.min(MAX_W / w, MAX_H / h);
@@ -127,13 +139,15 @@ onMounted(async () => {
 		canvas: canvasEl.value,
 		renderWidth: w,
 		renderHeight: h,
-		image: props.image,
+		image: imageBitmap,
 		fxs: FXS,
 	});
 
 	await renderer.setLayers(layers);
 
 	renderer.render();
+
+	closeWaiting();
 });
 
 onUnmounted(() => {
@@ -141,19 +155,26 @@ onUnmounted(() => {
 		renderer.destroy();
 		renderer = null;
 	}
+	if (imageBitmap != null) {
+		imageBitmap.close();
+		imageBitmap = null;
+	}
 });
 
 function save() {
-	if (layers.length === 0) {
+	if (layers.length === 0 || renderer == null || imageBitmap == null || canvasEl.value == null) {
 		cancel();
 		return;
 	}
 
-	renderer!.changeResolution(props.image.width, props.image.height); // 本番レンダリングのためオリジナル画質に戻す
-	renderer!.render(); // toBlobの直前にレンダリングしないと何故か壊れる
-	canvasEl.value!.toBlob((blob) => {
+	const closeWaiting = os.waiting();
+
+	renderer.changeResolution(imageBitmap.width, imageBitmap.height); // 本番レンダリングのためオリジナル画質に戻す
+	renderer.render(); // toBlobの直前にレンダリングしないと何故か壊れる
+	canvasEl.value.toBlob((blob) => {
 		emit('ok', new File([blob!], `image-${Date.now()}.png`, { type: 'image/png' }));
 		dialog.value?.close();
+		closeWaiting();
 	}, 'image/png');
 }
 
diff --git a/packages/frontend/src/components/MkUploaderDialog.vue b/packages/frontend/src/components/MkUploaderDialog.vue
index 0f25e255d5..15b106863c 100644
--- a/packages/frontend/src/components/MkUploaderDialog.vue
+++ b/packages/frontend/src/components/MkUploaderDialog.vue
@@ -297,9 +297,8 @@ function showMenu(ev: MouseEvent, item: typeof items.value[0]) {
 			icon: 'ti ti-sparkles',
 			text: i18n.ts._imageEffector.title,
 			action: async () => {
-				const imageBitmap = await window.createImageBitmap(item.file);
 				const { dispose } = os.popup(defineAsyncComponent(() => import('@/components/MkImageEffectorDialog.vue')), {
-					image: imageBitmap,
+					image: item.file,
 				}, {
 					ok: (file) => {
 						URL.revokeObjectURL(item.thumbnail);
@@ -313,10 +312,7 @@ function showMenu(ev: MouseEvent, item: typeof items.value[0]) {
 							triggerRef(items);
 						});
 					},
-					closed: () => {
-						imageBitmap.close();
-						dispose();
-					},
+					closed: () => dispose(),
 				});
 			},
 		});
@@ -353,18 +349,14 @@ function showMenu(ev: MouseEvent, item: typeof items.value[0]) {
 				icon: 'ti ti-plus',
 				text: i18n.ts.add,
 				action: async () => {
-					const imageBitmap = await window.createImageBitmap(item.file);
 					const { dispose } = os.popup(defineAsyncComponent(() => import('@/components/MkWatermarkEditorDialog.vue')), {
-						image: imageBitmap,
+						image: item.file,
 					}, {
 						ok: (preset) => {
 							prefer.commit('watermarkPresets', [...prefer.s.watermarkPresets, preset]);
 							changeWatermarkPreset(preset.id);
 						},
-						closed: () => {
-							imageBitmap.close();
-							dispose();
-						},
+						closed: () => dispose(),
 					});
 				},
 			}],
diff --git a/packages/frontend/src/components/MkWatermarkEditorDialog.vue b/packages/frontend/src/components/MkWatermarkEditorDialog.vue
index 81c0c72199..f8c11e9867 100644
--- a/packages/frontend/src/components/MkWatermarkEditorDialog.vue
+++ b/packages/frontend/src/components/MkWatermarkEditorDialog.vue
@@ -63,7 +63,7 @@ const $i = ensureSignin();
 
 const props = defineProps<{
 	preset?: WatermarkPreset | null;
-	image?: ImageBitmap | null;
+	image?: File | null;
 }>();
 
 const preset = reactive(deepClone(props.preset) ?? {
@@ -149,6 +149,7 @@ watch(sampleImageType, async () => {
 });
 
 let renderer: WatermarkRenderer | null = null;
+let imageBitmap: ImageBitmap | null = null;
 
 async function initRenderer() {
 	if (canvasEl.value == null) return;
@@ -168,10 +169,12 @@ async function initRenderer() {
 			image: sampleImage_2_3,
 		});
 	} else if (props.image != null) {
+		imageBitmap = await window.createImageBitmap(props.image);
+
 		const MAX_W = 1000;
 		const MAX_H = 1000;
-		let w = props.image.width;
-		let h = props.image.height;
+		let w = imageBitmap.width;
+		let h = imageBitmap.height;
 
 		if (w > MAX_W || h > MAX_H) {
 			const scale = Math.min(MAX_W / w, MAX_H / h);
@@ -183,7 +186,7 @@ async function initRenderer() {
 			canvas: canvasEl.value,
 			renderWidth: w,
 			renderHeight: h,
-			image: props.image,
+			image: imageBitmap,
 		});
 	}
 
@@ -193,10 +196,14 @@ async function initRenderer() {
 }
 
 onMounted(async () => {
+	const closeWaiting = os.waiting();
+
 	await sampleImage_3_2_loading;
 	await sampleImage_2_3_loading;
 
-	initRenderer();
+	await initRenderer();
+
+	closeWaiting();
 });
 
 onUnmounted(() => {
@@ -204,6 +211,10 @@ onUnmounted(() => {
 		renderer.destroy();
 		renderer = null;
 	}
+	if (imageBitmap != null) {
+		imageBitmap.close();
+		imageBitmap = null;
+	}
 });
 
 async function save() {