php — определить, горизонтальная картинка или вертикальная

while ($r = mysql_fetch_array($a))
{
   $image_name = $r['img_name'];
   $image_path = "/path/to/".$image_name;
   $image_ext = end(explode(".", $image_path));
   if ($image_ext == 'png')
   {
      $image_src = imagecreatefrompng($image_path);
   }
   else if ($image_ext == 'gif')
   {
      $image_src = imagecreatefromgif($image_path);
   }
   else
   {
      $image_src = imagecreatefromjpeg($image_path);
   }
   $width_src = imagesx($image_src);
   $height_src = imagesy($image_src);
   if ($width_src > $height_src)
   {
      $used_size = "width='100px'";
   }
   else
   {
      $used_size = "height='100px'";
   }
   imagedestroy($image_src);
   echo "<div style='width: 110px; height: 110px; float: left;'><img ".$used_size." src='/path/to/".$image_name."' alt='some_text' /></div>";
}