please elaborate on "in the past." because you can still do this. no feature was removed or added to prevent doing this.
if a forum is setup with the stock post attachment features enabled, you dont need to post your attachments with any third-party website or software.
lightbox (you referred to it "shadow box") is a photo gallery presentation option. there is nothing stopping you from getting the url to the full sized attached image by right-clicking (or long-pressing if on mobile) on the attachment preview thumbnail, and choosing "copy image url" to use that inlined anywhere within your post.
Here is an example of what I am talking about (images within post) in the link below. We only have 10,000 + members and now have a history forum so that all members and guest can view.
Yes we did have in the past a third party image loader which worked with the old version of UBB but was hoping that UBB would adopt the same format.
Link
CLICK HERE
