PHP - Image upload resizing script | Image resize by script

Process an image after upload.

code:

function process_image($image, $folder, $prefix = "", $newwidth = 800, $newheight = NULL, 
$allow = array("image/jpeg", "image/png", "image/gif"), $sizelimit = 2000000) {

  global $error;
  
  if (!is_dir($folder)) {
   mkdir($folder, 0777);
  }
  
  if (in_array($image["type"], $allow)) {
      if ($image["size"] < $sizelimit) {
          $uploadedfile = $image['tmp_name'];
          switch($image["type"]) {
              case "image/jpeg":
              $src = imagecreatefromjpeg($uploadedfile);
              list($width,$height)=getimagesize($uploadedfile);
              $ratio_orig = $width/$height;
              if ($newwidth/$newheight > $ratio_orig) {
              $newwidth = $newheight*$ratio_orig;
              } else {
              $newheight = $newwidth/$ratio_orig;
              }
              $tmp=imagecreatetruecolor($newwidth,$newheight);
              imagecopyresampled($tmp,$src,0,0,0,0,$newwidth,$newheight,$width,$height);
              $filename = $folder.$prefix.$image['name'];
              imagejpeg($tmp,$filename,100);
              imagedestroy($src);
              imagedestroy($tmp);
              return true;
          break;
          case "image/png":
              $src = imagecreatefrompng($uploadedfile);
              list($width,$height)=getimagesize($uploadedfile);
              $ratio_orig = $width/$height;
              if ($newwidth/$newheight > $ratio_orig) {
              $newwidth = $newheight*$ratio_orig;
              } else {
              $newheight = $newwidth/$ratio_orig;
              }
              $tmp=imagecreatetruecolor($newwidth,$newheight);
              imagecopyresampled($tmp,$src,0,0,0,0,$newwidth,$newheight,$width,$height);
              $filename = $folder.$prefix.$image['name'];
              imagepng($tmp,$filename);
              imagedestroy($src);
              imagedestroy($tmp);
              return true;
          break;
          case "image/gif":
              $src = imagecreatefromgif($uploadedfile);
              list($width,$height)=getimagesize($uploadedfile);
              $ratio_orig = $width/$height;
              if ($newwidth/$newheight > $ratio_orig) {
              $newwidth = $newheight*$ratio_orig;
              } else {
              $newheight = $newwidth/$ratio_orig;
              }
              $tmp=imagecreatetruecolor($newwidth,$newheight);
              imagecopyresampled($tmp,$src,0,0,0,0,$newwidth,$newheight,$width,$height);
              $filename = $folder.$prefix.$image['name'];
              imagegif($tmp,$filename);
              imagedestroy($src);
              imagedestroy($tmp);
              return true;
          break;
          }
      } else {
       $error = "File size to big.";
       return false;
      }
  } else {
   $error = "File type not allow.";
   return false;
  }
}

note: $image is an array of the image uploaded (from $_FILES)