Validated XF Owner
The update did nothing with the group Photo area.
Could you please right click on one of the missing photos and check the image properties to see if they actually exist on your server in the location shown when you right click on them? And what is the location?
Also, what version did you upgrade from when the images disappeared?
Did you manually delete the forum from the Admin->Forums->Nodes list before attempting to delete the group? (this was possible in older versions of the add-on so you could have done it a long time ago)