class.upload.php is a powerful and mature PHP class to manage uploaded files, and manipulate images in many ways. The script is available under a GPL license.
more info about the class
I've tried a lot of different pictures:
wii.jpg
ps3.png
MacBookPro.jpg
What browser do you use?
Firefox 3.0.5
On which system?
Client: Win XP
Serveur: Linux Debian
Which version of PHP?
5.2.8-0.dotdeb.1
Apache?
Apache/2.2.3