Currently images get badly aliased and less legible the more their size diverges from the original. To illustrate: <a href="http://i.imgur.com/oC1FCMP.png" rel="nofollow">http://i.imgur.com/oC1FCMP.png</a> (It's not just dedicated image editors that can do this - if you resize that image in your browser it'll do a fairly good job of it) You can mitigate the issue by making sure your images are close to the final size you want to use them at. However, this issue still limits the use of the zoom feature (as does the fact that the measuring stick's displayed number is also resized to be too small at low zoom levels, though that's a different issue) - at the very least it makes things uglier. It's not a huge problem by any means, but I think fixing it would be a nice quality of life thing.
