Yeah. I mean, the AO3 at least sets out to preserve and be stable, but nothing is guaranteed. I still really wish AO3 would get around to hosting images already. I have "archived" my art there, but of course it is only embedded, so if my own website went down it would all be gone (well I allow robots and archiving, so people could retrieve it with the Wayback Machine, probably, but in principle). And the images on LJ/DW would be broken too. I have stored it at deviantArt as well, but their rules about explicit stuff are fairly strict (most of mine is okay, but that's not true for everyone).