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.
I did some tests here, with a JPEG image, 5000x5000, and 10000x10000. The size was about under 300KB. I tried with 64MB memory limit, and it all worked fine, resizing images and all.
Send me the image, and the memory limit you have. In any case, your problem is very likely to be a memory issue.Reply
Send me the image, and the memory limit you have. In any case, your problem is very likely to be a memory issue.