function base64_encode_image ($filename=string,$filetype=string) {
    if ($filename && is_file($filename)) {
         $imgbinary = fread(fopen($filename, "r"), filesize($filename));
	 return 'data:image/' . $filetype . ';base64,' . base64_encode($imgbinary);
    } else {
	 $const = strtoupper(str_replace('.'.$filetype,'',$filename));
	 if (defined($const)){return constant($const);} else {return null;}
    }
}