DedeCMS图集中缩略图不显示怎么办

if($srcW<=$toW && $srcH<=$toH ) return true;

//增加小于缩略图尺寸处理开始
if($srcW<=$toW && $srcH<=$toH )
{
$ftoH=$toH;
$ftoW=$toH;
if(function_exists("imagecreatetruecolor"))
{
@$ni = imagecreatetruecolor($ftoW,$ftoH);
if($ni)
{
imagecopyresampled($ni,$im,0,0,0,0,$ftoW,$ftoH,$srcW,$srcH);
}
else
{
$ni=imagecreate($ftoW,$ftoH);
imagecopyresized($ni,$im,0,0,0,0,$ftoW,$ftoH,$srcW,$srcH);
}
}
else
{
$ni=imagecreate($ftoW,$ftoH);
imagecopyresized($ni,$im,0,0,0,0,$ftoW,$ftoH,$srcW,$srcH);
}
switch ($srcInfo[2])
{
case 1:
imagegif($ni,$toFile);
break;
case 2:
imagejpeg($ni,$toFile,100);
break;
case 3:
imagepng($ni,$toFile);
break;
case 6:
imagebmp($ni,$toFile);
break;
default:
return false;
}
imagedestroy($ni);
}
//增加小于缩略图尺寸处理结束