Well, its just a mild suggestion.
Most of the cases, users do not upload pictures.
However, for a certain forum (e.g., my forum), they post lots of pictures. And it should be more user-friendly to arrange pictures automatically with flanking lines. Or, maybe nodebb could add a switch in the system management panel, then let the administrator to choose automatically arrange pics or not.
As it currently stands, category is hard coded into NodeBB. It will require a lot of work to make the paths custom, but it is a planned feature. So, you will either have to just not change the path or get somebody to change all of the hard coded areas that need to be notified in the site code.