message: Update image-media.ts
diff: @@ -92,7 +92,7 @@ export async function createThumbnail(
  context.drawImage(element, 0, 0, targetWidth, targetHeight);
  let thumbnailPromise: Promise<Blob>;
  - if (canvas instanceof window.OffscreenCanvas) {
  + if (window.OffscreenCanvas && canvas instanceof window.OffscreenCanvas) {
  thumbnailPromise = canvas.convertToBlob({ type: mimeType });
  } else {
  thumbnailPromise = new Promise<Blob>(resolve => (canvas as HTMLCanvasElement).toBlob(resolve, mimeType));
  