Fatal Error: Allowed Memory Size of 8388608 Bytes exhausted (tried to allocate 6400 Bytes)

  public function scaleDownImage($src, $width_limit, $height_limit){
    $img_data = getimagesize($src);
    $types    = array(1=>'gif', 'jpeg', 'png');
    $type     = $types[$img_data[2]];	
    if($img_data[0] > $width_limit){
      eval('$im = imagecreatefrom' . $type . '($src);');
      $new_image_width  = $width_limit;
      $new_image_height = floor(($img_data[1] * $width_limit) / $img_data[0]);
      $new_image        = imagecreatetruecolor($new_image_width, $new_image_height);
      imagecopyresized($new_image, $im, 0, 0, 0, 0, $new_image_width, $new_image_height, $img_data[0], $img_data[1]);
      eval('image' . $type . '($new_image, $src);');
      $img_data[0]  = $new_image_width;
      $img_data[1]  = $new_image_height;
    }
    if($img_data[1] > $height_limit){
      eval('$im = imagecreatefrom' . $type . '($src);');
      $new_image_height = $height_limit;
      $new_image_width  = floor(($img_data[0] * $height_limit) / $img_data[1]);
      $new_image        = imagecreatetruecolor($new_image_width, $new_image_height);
      imagecopyresized($new_image, $im, 0, 0, 0, 0, $new_image_width, $new_image_height, $img_data[0], $img_data[1]);
      eval('image' . $type . '($new_image, $src);');
    }
  }