问GD LIbrary on a Mac："undefined function LIbrary\Image\Gd\imagecreatefrompng()“

EN

public function update(Request $request, $id)
{

  //Show the image
  echo '<img src="'.$_POST['img_val'].'" />';

  //Get the base-64 string from data
  $filteredData=substr($_POST['img_val'], strpos($_POST['img_val'], ",")+1);

  //Decode the string
  $unencodedData=base64_decode($filteredData);

  //Save the image
  $storagepath = storage_path('app/images/users/' . Auth::user()->id);
  $imgoutput = File::put($storagepath.'/flyer2.png', $unencodedData);


  return view('backend.flyers.index')->withImgoutput($imgoutput);
                                     //->withStoragepath($storagepath);

}