diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index ca301c5d38..897fa75436 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -3583,6 +3583,7 @@ _miRoom:
   material_metallic: "光沢"
   material_roughness: "粗さ"
   light_brightness: "明るさ"
+  advancedCustomize: "高度なアレンジ"
 
   _objects:
     woodRingFloorLamp: "リングシェードフロアランプ"
diff --git a/packages/frontend/src/pages/rooms/room.core.vue b/packages/frontend/src/pages/rooms/room.core.vue
index 34ed774626..0b55081535 100644
--- a/packages/frontend/src/pages/rooms/room.core.vue
+++ b/packages/frontend/src/pages/rooms/room.core.vue
@@ -785,9 +785,8 @@ function showOtherMenu(ev: PointerEvent) {
 	right: 16px;
 	z-index: 1;
 	padding: 16px;
-	box-sizing: border-box;
 	width: 300px;
-	max-height: 100%;
+	max-height: calc(100% - 16px - 16px);
 	box-sizing: border-box;
 	overflow: auto;
 	border-radius: 12px;
diff --git a/packages/frontend/src/pages/rooms/room.object-customize-form.vue b/packages/frontend/src/pages/rooms/room.object-customize-form.vue
index 7e5f6c93e1..5e81ae9ac8 100644
--- a/packages/frontend/src/pages/rooms/room.object-customize-form.vue
+++ b/packages/frontend/src/pages/rooms/room.object-customize-form.vue
@@ -22,12 +22,14 @@ SPDX-License-Identifier: AGPL-3.0-only
 				<MkInput :modelValue="getHex(options[k].color)" type="color" :throttle="300" @update:modelValue="v => { const c = getRgb(v); if (c != null) updateMaterialColor(k, c); }">
 					<template #label>{{ i18n.ts.color }}</template>
 				</MkInput>
-				<MkRange :continuousUpdate="true" :min="0" :max="1" :step="0.1" :modelValue="options[k].metallic" @update:modelValue="v => updateMaterialMetallic(k, v)">
-					<template #label>{{ i18n.ts._miRoom.material_metallic }}</template>
-				</MkRange>
-				<MkRange :continuousUpdate="true" :min="0" :max="1" :step="0.1" :modelValue="options[k].roughness" @update:modelValue="v => updateMaterialRoughness(k, v)">
-					<template #label>{{ i18n.ts._miRoom.material_roughness }}</template>
-				</MkRange>
+				<template v-if="advancedCustomize">
+					<MkRange :continuousUpdate="true" :min="0" :max="1" :step="0.1" :modelValue="options[k].metallic" @update:modelValue="v => updateMaterialMetallic(k, v)">
+						<template #label>{{ i18n.ts._miRoom.material_metallic }}</template>
+					</MkRange>
+					<MkRange :continuousUpdate="true" :min="0" :max="1" :step="0.1" :modelValue="options[k].roughness" @update:modelValue="v => updateMaterialRoughness(k, v)">
+						<template #label>{{ i18n.ts._miRoom.material_roughness }}</template>
+					</MkRange>
+				</template>
 			</div>
 			<div v-else-if="s.type === 'light'" class="_gaps_s">
 				<!-- debounce or throttleしないとカラーピッカー上で高速でなぞったときになぜか無限ループになる。ワーカーとの間でラグがあるため、少し前の値がまたmodelValueとしてフィードバックされてしまうためだと思われる -->
@@ -68,6 +70,8 @@ SPDX-License-Identifier: AGPL-3.0-only
 				<MkRange :continuousUpdate="true" :min="0" :max="1000" :step="1" :modelValue="options[k]" @update:modelValue="v => emit('update', k, v)"></MkRange>
 			</div>
 		</MkFolder>
+
+		<MkSwitch v-model="advancedCustomize">{{ i18n.ts._miRoom.advancedCustomize }}</MkSwitch>
 	</div>
 </div>
 </template>
@@ -76,7 +80,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { } from 'vue';
 import * as Misskey from 'misskey-js';
 import { getHex, getRgb } from 'misskey-world/src/utility.js';
-import type { ObjectSchemaDef } from 'misskey-world/src/room/object.js';
+import type { ObjectSchemaDef, RawOptions } from 'misskey-world/src/room/object.js';
 import { i18n } from '@/i18n.js';
 import MkButton from '@/components/MkButton.vue';
 import MkSelect from '@/components/MkSelect.vue';
@@ -88,6 +92,7 @@ import { chooseDriveFile } from '@/utility/drive.js';
 import MkRadios from '@/components/MkRadios.vue';
 import MkFolder from '@/components/MkFolder.vue';
 import { OBJECT_UI_DEFS } from '@/world/room/object-ui-defs.js';
+import { prefer } from '@/preferences.js';
 
 const props = defineProps<{
 	schema: ObjectSchemaDef<any>;
@@ -99,6 +104,8 @@ const emit = defineEmits<{
 	(ev: 'update', k: string, v: any): void;
 }>();
 
+const advancedCustomize = prefer.model('world.room.advancedCustomize');
+
 function changeImageType(k: string, type: string) {
 	emit('update', k, { ...props.options[k], type, driveFileId: type === '_custom_' ? props.options[k].driveFileId : null });
 }
@@ -121,6 +128,13 @@ async function changeImage(k: string) {
 			});
 			return;
 		}
+		if (Math.max(file.properties.width ?? 0, file.properties.height ?? 0) > 2048) {
+			os.alert({
+				type: 'error',
+				text: 'The image dimensions exceed the limit of 2048x2048 pixels.',
+			});
+			return;
+		}
 		props.addFileAttachment(file);
 		emit('update', k, {
 			...props.options[k],
diff --git a/packages/frontend/src/preferences/def.ts b/packages/frontend/src/preferences/def.ts
index f75cf52577..daefded184 100644
--- a/packages/frontend/src/preferences/def.ts
+++ b/packages/frontend/src/preferences/def.ts
@@ -548,6 +548,9 @@ export const PREF_DEF = definePreferences({
 	'world.separateRenderingThread': {
 		default: true,
 	},
+	'world.room.advancedCustomize': {
+		default: false,
+	},
 
 	'experimental.stackingRouterView': {
 		default: false,
diff --git a/packages/i18n/src/autogen/locale.ts b/packages/i18n/src/autogen/locale.ts
index ed495a0f2c..768de9673c 100644
--- a/packages/i18n/src/autogen/locale.ts
+++ b/packages/i18n/src/autogen/locale.ts
@@ -13370,6 +13370,10 @@ export interface Locale extends ILocale {
          * 明るさ
          */
         "light_brightness": string;
+        /**
+         * 高度なアレンジ
+         */
+        "advancedCustomize": string;
         "_objects": {
             /**
              * リングシェードフロアランプ