Fatal Error, time exceeded.

[Red Blaze]

I get a Fatal Error Maximum execution time of 30 seconds exceeded on line 19.

while($counter <= count($photos_uploaded)) {
 if($photos_uploaded['size'][$counter] > 0) {
   if(!array_key_exists($photos_uploaded['type'][$counter], $photo_types)) {
     $result_final .= 'File ' . ($counter + 1) .
       ' is not a photo<br />';
   } else {
     // Great the file is an image, we will add this file
   }
 }
}

That's the block of code that starts at line 19. Any way I can make the code simpler so that it won't exceed the 30 second execution limit?