message: ensure file extension for image download
diff: @@ -87,8 +87,8 @@ export class ImageControls<P, S extends ImageControlsState> extends CollapsableC
  canvasCtx.putImageData(imageData, 0, 0)
  await ctx.update('Downloading image...')
  - const blob = await canvasToBlob(canvas)
  - download(blob, 'molstar-image')
  + const blob = await canvasToBlob(canvas, 'png')
  + download(blob, 'molstar-image.png')
  })
  }
  