Description:
------------
function: exif_imagetype do not exists! Fatal error: Call to undefined function

Reproduce code:
---------------
function chk_image($type,$imagepath) {
         $transtype = "";
    if(file_exists($imagepath)) {
         switch($type) {
              case "gif": $transtype = IMAGETYPE_GIF;   break;
              case "jpg": $transtype = IMAGETYPE_JPEG;  break;
              case "png": $transtype = IMAGETYPE_PNG;   break;
              case "swf": $transtype = IMAGETYPE_SWF;   break;
              case "psd": $transtype = IMAGETYPE_PSD;   break;
              case "bmp": $transtype = IMAGETYPE_BMP;   break;
         }
         if (exif_imagetype($imagepath) == $transtype) {
                return true;
         } else {
                return false;
         }
    } else {
      return false;
      //echo "Error: Image not Found<br>";
    }
}
puts out: Fatal error: Call to undefined function exif_imagetype