UBB.threads has always had attachments, and has had Gallery Forums for much of the v7.5 series. Permissions are all handled through the Forum Permissions area (for both features), the difference really is:
Gallery Forums are treated like a standard, run of the mill photo gallery, images are compressed as their uploaded. Attachments are basically the same thing, only they are not compressed and you can enter the TYPE of files to allow to be uploaded (hence "attachments" as it's more than photos), and images are not compressed (until v7.6.1 is released).
With attachments there are several areas for customization (and as I'm building this list off of v7.6.1 it'll vary wording based on whatever version you're currently using; keep in mind that most of this has existed for most of v7.5.x):
Forum Permissions: CP -> Permissions -> Forum
Attachment Settings: Attachment Options: CP -> Master Settings -> Feature Settings -> Attachments Tab (Attachment storage directory, URL, and Allowed Extensions)
Gallery Settings: CP -> Master Settings -> Gallery Settings (graphics library, max height/width, image quality)
The following are attachment permissions for each forum (again, in the forum permission section):
Can Download Attachments, Max Size of File Attachments, Total # of Attachments
You can toggle the size of the "Show Images Inline" option by going to CP -> Display Settings -> General -> Topic & Post Page Settings and changing "Max File Size for Displaying Uploaded Images Inline" setting (if you WANT them to automatically display vs display as a list of uploads).
