Good question on nuking attachments yourselves. I'll try and log in with the test account and see if anything shows up. I'm inclined to say "no" though as it's probably tied to editing time.
Does anyone here have, or administer (from the server side) a Simple Machines forum?
I simply have no idea of what things look like on that other side, so am hesitant to make changes on this side for fear of glitching something. My initial thoughts are that if we are on some hard physical limit (or amount of space that Oleg purchased) we'll just have to turn off attachment posting and then maybe delete old images from say, 2007, which would free up enough space to allow continued avatars. Or if it's a matter of purchasing more space on the server, we'd have to contact Oleg and I'd be willing to pay for some more gigs myself if we could make that work.
If there's a ton of space available now, we just double the space allocation on this side for the attachment directory, then not worry about it again for another 10 years. :)
Again, there's a bunch of quick and easy "fixes" available on this side of the forum, but with zero knowledge of what things look like on the other side, I'm hesitant to change anything here as far as storage space increases for fear of causing an error on the server side.