I was mistaken - it has been a while since I checked the media gallery settings. There is no limit in terms of the images that you can post in the forum.
The primary reason why there is a limit is to prevent people from loading large images without compression onto the site. 100MB if you compress your images to 100K is 1000 images. (The largest current gallery is 180 images) If you load them uncompressed at 10MB per image... you get 10.
That is why I said I had to check into our compression utility and make sure everything was working properly. The site should automatically compress images if they are uncompressed. It sounds to me like you are loading images with an average size of 4MB... so you are running out of room quickly.
(An example of a 90K image)
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