Could this answer be removed?
Fixed that for you. Moderators can still delete posts on locked questions. I've deleted those answers for now.
This question was created way before imgur came into the picture at Stack Overflow so there's probably a number of broken images out there.
If you have a copy (and the rights) of the image I'd recommend uploading it to imgur (through the image box on the page) so it's stored there for posterity and then bringing it up on meta with the link to the image and we'll restore the answer on the post with the working image link.
Removing the lock just to remove a single answer (or ten) is a bit of a hassle, not really worth it.
Deleting the question on the other hand...