Personally, I'm impressed by how the image dimensions were mapped to the image, not the fact that it can be done at all. There are plenty of boring and simple ways to map dimensions to an image. This was clever and well-implemented, imo. :)
Make the Zeus image tall and skinny. Then make it short and wide. Then make it square.
So this has over 1000 upvotes because it's good art, not because it's an interesting algorithm?
I think it's because it invokes the "Oh, that's so cool" feeling in people. It's a good feeling, even if it isn't due to learning about an interesting algorithm. Hackers and Painters I guess.
I think it's both. I haven't dug into the source code like others have, and whatever algorithms are in use may not be generalizable, but the tweening is cool and the art is cool.
I have to agree I was surprised by the number of upvotes as it didn't strike that chord with me, but I can see it has with other HN-ers so who am I to argue. I am impressed by the obvious amount of effort gone into it and the originality.