Image functions

thebay

Can the following functions support other image format such as
gif, png? where to check that. I want to generate a
thumbnail image for any image.

$src = ImageCreateFromJpeg($image);
$dst = ImageCreate($tn_width,$tn_height);
ImageCopyResized($dst, $src, 0, 0, 0, 0,
$tn_width,$tn_height,$width,$height);
header('Content-type: image/jpeg');
ImageJpeg($dst, null, -1);
ImageDestroy($src);
ImageDestroy($dst);

crosbystillsnas

yes, they do.
ImageCreateFromJpeg()
ImageCreateFromGif()
ImageCreateFromPng()

you find information in the manual:
http://de2.php.net/manual/en/print/ref.image.php

creating thumbnails from a directory, you can use getImageSize() first as this returns width, height, type...
switch the returned type and use the corresponding ImageCreateFrom...()