Get remote pictures to local (audio and video are also available)

Remote pictures are obtained locally (audio and video are also acceptable) and cannot be specially encrypted.

function GrabImage($url,$filename="")
{
if($url==""):return false;endif;
 if($filename=="") {
 $ext=strrchr ($url,".");
 if($ext!=".gif" && $ext!=".jpg"):return false;endif;
 $filename_r=time().rand(10,9000) .$ext;
 $filename='get_images/'.$filename_r;
 }
 ob_start();
 readfile($url);
 $img = ob_get_contents();
 ob_end_clean();
 $size = strlen($ img);
 $fp2=@fopen($filename, "a");
 fwrite($fp2,$img);
 fclose($fp2);
 return $filename_r;
}

$img=GrabImage(" http://cdn.iciba.com/news/word/big_2014-07-16b.jpg");
if($img):echo '<img src="get_images/'.$img. '">';
else:echo "false";
endif;