fix loading spinner

Signed-off-by: eternal-flame-AD <yume@yumechi.jp>

packages/backend/src/server/pug-filters.ts

@@ -7,6 +7,6 @@ export const commonPugFilters = {
             throw new Error('Invalid mimeType');
         }
         const dataURI = `data:${options.mimeType};base64,${Buffer.from(data).toString('base64')}`;
-        return `<${options.tagName} data="${dataURI}"></${options.tagName}>`;
+        return `<${options.tagName} src="${dataURI}"></${options.tagName}>`;
     }
 } as const;