创建图像缩略图需要许多时间，此代码将有助于了解缩略图的逻辑。
代码如下:
/**********************
*@filename - path to the image
*@tmpname - temporary path to thumbnail
*@xmax - max width
*@ymax - max height
*/
function resize_image($filename, $tmpname, $xmax, $ymax)
{
$ext = explode(., $filename);
$ext = $ext[count($ext)-1];
if($ext == jpg || $ext == jpeg)
$im = imagecreatefromjpeg($tmpname);
elseif($ext == png)
$im = imagecreatefrompng($tmpname);
elseif($ext == gif)
$im = imagecreatefromgif($tmpname);
$x = imagesx($im);
$y = imagesy($im);
if($x return $im;
if($x >= $y) {
$newx = $xmax;
$newy = $newx * $y / $x;
}
else {
$newy = $ymax;
$newx = $x / $y * $newy;
}
$im2 = imagecreatetruecolor($newx, $newy);
imagecopyresized($im2, $im, 0, 0, 0, 0, floor($newx), floor($newy), $x, $y);
return $im2;
}
这里是摘自脚本之家之前发布的文章。更多的技巧可以参考。