Okay there are a couple of things to check.
First.
How do you access the forum permissions.
The reason I ask is you might be just editing the default permissions template not the actual forum permissions.
Second.
when you enter the file size there is a note . It displays what the file size limit is by your host.
What does it say?
It will be something like:
If this forum is a gallery forum, this setting dictates how large each image may be. Max size set in php.ini is 8M, so you may not exceed this size.
Third is goto:
Control Panel » Permission Checks
look for anything that fails in the gallery folders.
You can click on on line.
Maybe you have a file permission issue.
