My two solutions:
1)
-All gang picture uploads remain the same for players (they won't notice a difference)

-EXCEPT on our end, all pictures are logged.
-Staff go through the logged pictures daily..any inappropriate find, will be deleted and the gang banned from uploads until further staff review/action

This solution still may allow players to upload inappropriate pictures for a few seconds or minutes for others to see, but the upload is still logged and admins will still see it even if the player changes the picture after 1 second.

2)
-Charge players gralats for every gang picture update, and still implement Solution 1.