I host my own Fedora 10 server that I use for this blog and recently noticed that when I uploaded photos using the Photo Uploader, they were not resized and I was not offered a thumbnail, medium or large size, only ever the full size. I investigated to see what the problem might be and it seems that Fedora isn’t shipped with php-gd installed by default so image resizing simply doesn’t work.
As root, a quick:
yum install php-gd
service httpd restart
did the trick and my images are now resized properly at upload time!
If you find you can’t upload at all, something to check is that the apache user has relevant permissions to your upload folder!
Lewis