draco2k

If you are still having problems after trying all the great suggestions here, then selinux might be getting in your way if you are running it.

For a quick test:

1. turn selinux off (as root: setenforce 0)
2. try to save your file
3. turn selinux back on (as root: setenforce 1)

If you were able to save your file, then the selinux context on your uploads directory is wrong.

To correct (as root):

1. cd to the parent folder of the uploads directory
2. use the chown -R <uname>: uploads command to ensure that the uploads directory and all sub-directories are owned by the uid of the webserver (e.g. chown -R apache: uploads)
3. use the command restorecon -R uploads to ensure that the uploads directory and any sub-directories have the correct selinux security context

After this you should be able to save your images.

I hope this helps!