Perhaps I'm missing something but I don't see a way of viewing a series of thumbnails on a post without returning to the original post.
Would it not be possible to include a forward arrow?
I don't post much these days, but I read the site daily.
There seems to be at least three different types of posts. One pic at a time, as described by the OP, then there's the "magnifying glass", where you hover on a picture and open a separate pop-up with a magnified view. Then, there's the 'click thru slide show'....
I wonder where these come from... I'm interested in seeing where this will go.
I completely understand the desire to scroll through photos. Unfortunately, getting that functionality isn't possible without a complete upgrade to our forum software. That's been on the to-do list for some time, but it's a huge project that keeps getting put off. It has to happen eventually.
To answer Michaels question...
The thumbnails are just inserted as attachments (the "paperclip" icon)
Attachments can be shown as full size images as well
The "zooming" photos are inserted from your photo gallery.