Many times when tryin to answer somebodies question I wish I had a pic to put with it. I don't mean like full plane pics. I mean like closeups of firewalls, control horn fastening, servo installs, etc.
If you search around the forums all these pics are already there but that could take hours.
I'm thinkin a page with links to different sections of a plane.

firewalls
tank installations
servo installations
pushrods, nyrods
control surface hookups
landing gear & tail wheels
technical drawings
etc etc.

Each of these words was a link to a page with say 12 or 15 user submitted thumbnails of closeups of various ways of doing each thing.
Then when someone asks about servo bind I could just pop over to the "servo installations" page, save the pic that most accurately describes my answer, then upload it with my post.
Like I said, user submitted photos with a limit of 15 or so. (someone would have to choose the photos on your end) if ya got to many it would take to long to browse through them.
Technical drawings like a few different airfoils, incedence, thrust line, etc would also be great to get at quickly for a post.
Kinda like your current gallery only broken way down into individual sections of a plane/ boat/ car etc.
Users could not upload directly to the pages. Users would upload to you, a pic that they think would be helpful in answering a question. Then you could pick and choose a variety of these pics and place them in the proper category for viewing/ saving or whetever. Once you feel that you have a wide enough variety to choose from you simply don't add any more. Occasionally as new pics are sent your way you may come accross one that you think is different from the others enough that you can add to the page.

I hope ya understand what I'm talkin about here.