这段PHP本来是把titlepic里的外链图片自动下载，我想让它在下载时自动缩略成固定大小的图片。求教应该怎么修改呢？

$sqltext="SELECT id,titlepic FROM {$dbtbpre}_article where titlepic like 'http://%' order by id limit 1"; $r=$empire->fetch1($sqltext); if($r) { $path=ECMS_PATH."uploads\\pic\\"; $yname=$path.basename($r[titlepic]); $filename='/uploads/pic/'.basename($r[titlepic]); if(file_exists($yname)&&filesize($yname)>0) { echo($yname."已存在
"); //文件存在 //exit('s:'.filesize($yname)); } else { echo($yname."
down:".$r[titlepic]); $string=ReadFiletext($r[titlepic]); WriteFiletext_n($yname,$string); sleep(1); } $sqltext="update {$dbtbpre}_article set titlepic='$filename' where id='$r[id]'"; echo('
'.$sqltext); $empire->query($sqltext); sleep(1); echo""; } else { //echo""; echo"完成"; } db_close(); $empire=null;