diff --git a/.config/example.yml b/.config/example.yml
index 900ac0905..02661b7fb 100644
--- a/.config/example.yml
+++ b/.config/example.yml
@@ -96,6 +96,9 @@ id: 'aid'
 # Max note length, should be < 8000.
 #maxNoteLength: 3000
 
+# Maximum lenght of an image caption or file comment (default 1500, max 8192)
+#maxCaptionLength: 1500
+
 # Whether disable HSTS
 #disableHsts: true
 
diff --git a/packages/backend/migration/1677935903517-DriveComment.js b/packages/backend/migration/1677935903517-DriveComment.js
new file mode 100644
index 000000000..41c7556f0
--- /dev/null
+++ b/packages/backend/migration/1677935903517-DriveComment.js
@@ -0,0 +1,11 @@
+export class DriveComment1677935903517 {
+    name = 'DriveComment1677935903517'
+
+    async up(queryRunner) {
+        await queryRunner.query(`ALTER TABLE "drive_file" ALTER "comment" TYPE character varying(8192)`);
+    }
+
+    async down(queryRunner) {
+        await queryRunner.query(`ALTER TABLE "drive_file" ALTER "comment" TYPE character varying(512)`);
+    }
+}
diff --git a/packages/backend/src/config/types.ts b/packages/backend/src/config/types.ts
index e9c42c08f..ed9b0ece0 100644
--- a/packages/backend/src/config/types.ts
+++ b/packages/backend/src/config/types.ts
@@ -74,6 +74,7 @@ export type Source = {
 	maxUserSignups?: number;
 	isManagedHosting?: boolean;
 	maxNoteLength?: number;
+	maxCaptionLength?: number;
 	deepl: {
 		managed?: boolean;
 		authKey?: string;
diff --git a/packages/backend/src/const.ts b/packages/backend/src/const.ts
index 82a093100..7e8f96444 100644
--- a/packages/backend/src/const.ts
+++ b/packages/backend/src/const.ts
@@ -1,7 +1,12 @@
 import config from "@/config/index.js";
+import { DB_MAX_IMAGE_COMMENT_LENGTH } from "@/misc/hard-limits.js";
 
 export const MAX_NOTE_TEXT_LENGTH =
 	config.maxNoteLength != null ? config.maxNoteLength : 3000; // <- should we increase this?
+export const MAX_CAPTION_TEXT_LENGTH = Math.min(
+	config.maxCaptionLength ?? 1500,
+	DB_MAX_IMAGE_COMMENT_LENGTH,
+);
 
 export const SECOND = 1000;
 export const SEC = 1000; // why do we need this duplicate here?
diff --git a/packages/backend/src/misc/hard-limits.ts b/packages/backend/src/misc/hard-limits.ts
index 4ba90293c..51d2c0f5d 100644
--- a/packages/backend/src/misc/hard-limits.ts
+++ b/packages/backend/src/misc/hard-limits.ts
@@ -10,4 +10,4 @@ export const DB_MAX_NOTE_TEXT_LENGTH = 8192;
  * Maximum image description length that can be stored in DB.
  * Surrogate pairs count as one
  */
-export const DB_MAX_IMAGE_COMMENT_LENGTH = 512;
+export const DB_MAX_IMAGE_COMMENT_LENGTH = 8192;
diff --git a/packages/backend/src/models/entities/drive-file.ts b/packages/backend/src/models/entities/drive-file.ts
index 1fa91b1a9..32e19bc6e 100644
--- a/packages/backend/src/models/entities/drive-file.ts
+++ b/packages/backend/src/models/entities/drive-file.ts
@@ -9,6 +9,7 @@ import {
 import { id } from "../id.js";
 import { User } from "./user.js";
 import { DriveFolder } from "./drive-folder.js";
+import { DB_MAX_IMAGE_COMMENT_LENGTH } from "@/misc/hard-limits.js";
 
 @Entity()
 @Index(['userId', 'folderId', 'id'])
@@ -69,7 +70,8 @@ export class DriveFile {
 	public size: number;
 
 	@Column('varchar', {
-		length: 512, nullable: true,
+		length: DB_MAX_IMAGE_COMMENT_LENGTH,
+		nullable: true,
 		comment: 'The comment of the DriveFile.',
 	})
 	public comment: string | null;
diff --git a/packages/backend/src/server/api/endpoints/admin/meta.ts b/packages/backend/src/server/api/endpoints/admin/meta.ts
index 1808de118..c8c639f50 100644
--- a/packages/backend/src/server/api/endpoints/admin/meta.ts
+++ b/packages/backend/src/server/api/endpoints/admin/meta.ts
@@ -1,6 +1,6 @@
 import config from "@/config/index.js";
 import { fetchMeta } from "@/misc/fetch-meta.js";
-import { MAX_NOTE_TEXT_LENGTH } from "@/const.js";
+import { MAX_NOTE_TEXT_LENGTH, MAX_CAPTION_TEXT_LENGTH } from "@/const.js";
 import define from "../../define.js";
 
 export const meta = {
@@ -86,6 +86,11 @@ export const meta = {
 				optional: false,
 				nullable: false,
 			},
+			maxCaptionTextLength: {
+				type: "number",
+				optional: false,
+				nullable: false,
+			},
 			emojis: {
 				type: "array",
 				optional: false,
@@ -499,6 +504,7 @@ export default define(meta, paramDef, async (ps, me) => {
 		backgroundImageUrl: instance.backgroundImageUrl,
 		logoImageUrl: instance.logoImageUrl,
 		maxNoteTextLength: MAX_NOTE_TEXT_LENGTH, // 後方互換性のため
+		maxCaptionTextLength: MAX_CAPTION_TEXT_LENGTH,
 		defaultLightTheme: instance.defaultLightTheme,
 		defaultDarkTheme: instance.defaultDarkTheme,
 		enableEmail: instance.enableEmail,
diff --git a/packages/backend/src/server/api/endpoints/meta.ts b/packages/backend/src/server/api/endpoints/meta.ts
index 476a0c29f..4dc1c941e 100644
--- a/packages/backend/src/server/api/endpoints/meta.ts
+++ b/packages/backend/src/server/api/endpoints/meta.ts
@@ -2,8 +2,7 @@ import { IsNull, MoreThan } from "typeorm";
 import config from "@/config/index.js";
 import { fetchMeta } from "@/misc/fetch-meta.js";
 import { Ads, Emojis, Users } from "@/models/index.js";
-import { DB_MAX_NOTE_TEXT_LENGTH } from "@/misc/hard-limits.js";
-import { MAX_NOTE_TEXT_LENGTH } from "@/const.js";
+import { MAX_NOTE_TEXT_LENGTH, MAX_CAPTION_TEXT_LENGTH } from "@/const.js";
 import define from "../define.js";
 
 export const meta = {
@@ -178,6 +177,11 @@ export const meta = {
 				optional: false,
 				nullable: false,
 			},
+			maxCaptionTextLength: {
+				type: "number",
+				optional: false,
+				nullable: false,
+			},
 			emojis: {
 				type: "array",
 				optional: false,
@@ -456,6 +460,7 @@ export default define(meta, paramDef, async (ps, me) => {
 		backgroundImageUrl: instance.backgroundImageUrl,
 		logoImageUrl: instance.logoImageUrl,
 		maxNoteTextLength: MAX_NOTE_TEXT_LENGTH, // 後方互換性のため
+		maxCaptionTextLength: MAX_CAPTION_TEXT_LENGTH,
 		emojis: instance.privateMode && !me ? [] : await Emojis.packMany(emojis),
 		defaultLightTheme: instance.defaultLightTheme,
 		defaultDarkTheme: instance.defaultDarkTheme,
diff --git a/packages/backend/src/server/nodeinfo.ts b/packages/backend/src/server/nodeinfo.ts
index a7fa0de4c..8563573d4 100644
--- a/packages/backend/src/server/nodeinfo.ts
+++ b/packages/backend/src/server/nodeinfo.ts
@@ -3,7 +3,7 @@ import config from "@/config/index.js";
 import { fetchMeta } from "@/misc/fetch-meta.js";
 import { Users, Notes } from "@/models/index.js";
 import { IsNull, MoreThan } from "typeorm";
-import { MAX_NOTE_TEXT_LENGTH } from "@/const.js";
+import { MAX_NOTE_TEXT_LENGTH, MAX_CAPTION_TEXT_LENGTH } from "@/const.js";
 import { Cache } from "@/misc/cache.js";
 
 const router = new Router();
@@ -85,6 +85,7 @@ const nodeinfo2 = async () => {
 			enableHcaptcha: meta.enableHcaptcha,
 			enableRecaptcha: meta.enableRecaptcha,
 			maxNoteTextLength: MAX_NOTE_TEXT_LENGTH,
+			maxCaptionTextLength: MAX_CAPTION_TEXT_LENGTH,
 			enableTwitterIntegration: meta.enableTwitterIntegration,
 			enableGithubIntegration: meta.enableGithubIntegration,
 			enableDiscordIntegration: meta.enableDiscordIntegration,
diff --git a/packages/client/src/components/MkMediaCaption.vue b/packages/client/src/components/MkMediaCaption.vue
index ff195974a..7168d8723 100644
--- a/packages/client/src/components/MkMediaCaption.vue
+++ b/packages/client/src/components/MkMediaCaption.vue
@@ -39,6 +39,7 @@ import MkButton from '@/components/MkButton.vue';
 import bytes from '@/filters/bytes';
 import number from '@/filters/number';
 import { i18n } from '@/i18n';
+import { instance } from '@/instance';
 
 export default defineComponent({
 	components: {
@@ -87,8 +88,9 @@ export default defineComponent({
 
 	computed: {
 		remainingLength(): number {
-			if (typeof this.inputValue !== "string") return 512;
-			return 512 - length(this.inputValue);
+			const maxCaptionLength = instance.maxCaptionTextLength ?? 512;
+			if (typeof this.inputValue !== "string") return maxCaptionLength;
+			return maxCaptionLength - length(this.inputValue);
 		}
 	},