After upgrading to 6.22 my users noticed that there is no longer a box under the image for the IMG BB code unless there is a medium sized image.
Example:
Xplodor - Ford Explorer Ranger Photo Gallery at Serious Explorations
I do have the option enabled in my control panel. You can see it operating as expected here:
Moab 2002 - Ford Explorer Ranger Photo Gallery at Serious Explorations