With regards to the compatibility versions might be good to add a "all" or something similar in terms to indicate that the resource is compatible with all versions of xenforo. Since graphics will work on all versions unless not checking the box indicates that it's compatible with all versions.
The issue I have with "All" is that it implies future version compatibility which may not be the case. It's more edge case for graphics obviously, though there are situations where a new version could mean that the images don't really fit with new concepts. Selecting none is probably more appropriate if you'd rather not select all of them and maintain/check this for future versions.
That's up to you and Mike. I'm merely posting a suggestion for you and your site (xenforo.com) so whether or not you want to apply such changes is your own call I'll style it for my site but thought I'd throw the suggestion here for this site.