Dedecms缩略图失真模糊的解决方法

function thumb($imgurl, $width, $height, $bg = true){global $cfg_mainsite,$cfg_multi_site;$thumb = eregi("http://",$imgurl)?str_replace($cfg_mainsite,'',$imgurl):$imgurl;list($thumbname,$extname) = explode('.',$thumb);$newthumb = $thumbname.'_'.$width.'_'.$height.'.'.$extname;if(!$thumbname || !$extname || !file_exists(DEDEROOT.$thumb)) return $imgurl;if(!file_exists(DEDEROOT.$newthumb)){include_once DEDEINC.'/image.func.php';if($bg==true){ImageResizeNew(DEDEROOT.$thumb, $width, $height, DEDEROOT.$newthumb);}else{ImageResize(DEDEROOT.$thumb, $width, $height, DEDEROOT.$newthumb);}}return $cfg_multi_site=='Y'?$cfg_mainsite.$newthumb:$newthumb;}