Is it possible to make this feature available within the forum?
I wanted to post a screenshot of a website today, but had to upload to my site before I could do so.

One of the problems with off-site images is that after a while, they get deleted.

What I have done is create a personal photo album in these forums -- mine here -- then I just add an image to that, and post a regular image link to it in the main forum. Like this example:

This is not as easy as your suggestion -- just as much work as an off-site image -- but it does have the advantage of keeping the image in these forums.