diff --git a/src/client/assets/thumbnail-not-available.png b/src/client/assets/thumbnail-not-available.png
new file mode 100644
index 000000000..07cad9919
Binary files /dev/null and b/src/client/assets/thumbnail-not-available.png differ
diff --git a/src/misc/get-drive-file-url.ts b/src/misc/get-drive-file-url.ts
index 067db8a5d..f2b0f8b00 100644
--- a/src/misc/get-drive-file-url.ts
+++ b/src/misc/get-drive-file-url.ts
@@ -8,7 +8,7 @@ export default function(file: IDriveFile, thumbnail = false): string {
 
 	if (file.metadata.withoutChunks) {
 		if (thumbnail) {
-			return file.metadata.thumbnailUrl || file.metadata.webpublicUrl || (isImage ? file.metadata.url : null);
+			return file.metadata.thumbnailUrl || file.metadata.webpublicUrl || (isImage ? file.metadata.url : '/assets/thumbnail-not-available.png');
 		} else {
 			return file.metadata.webpublicUrl || file.metadata.url;
 		}
diff --git a/src/server/file/send-drive-file.ts b/src/server/file/send-drive-file.ts
index e0208f3fa..b22124240 100644
--- a/src/server/file/send-drive-file.ts
+++ b/src/server/file/send-drive-file.ts
@@ -73,7 +73,7 @@ export default async function(ctx: Koa.BaseContext) {
 				await sendRaw();
 			} else {
 				ctx.status = 404;
-				await send(ctx as any, '/dummy.png', { root: assets });
+				await send(ctx as any, '/thumbnail-not-available.png', { root: assets });
 			}
 		}
 	} else if ('web' in ctx.query) {