I often see questions from new users that really need some pictures in order to be answered, but the low-rep users aren't allowed to post pictures. Currently the workaround is for them to host the image externally, include a (broken to avoid spam filter) link to it, and then hope some editor comes along and moves it to SE's imgur and gives it a proper inclusion. This is stupid. I know you're afraid of trolls posting vulgar images or whatever, but there has to be some route for new users to post diagrams.
One way would be to tie it into the edit review system. When a new user tries to include an image in their question, most of the question goes live, but the image is treated as an additional edit by an unvetted user, which has to be reviewed by a high-rep user before it goes live.
There are probably other solutions, too, like hiding the image until the question gets 2 upvotes, etc.