Indeed, upload what you find for sure. If you edit it, another guy's going to find this thing and upload it and forget to parent or whatever, and that will be confusing.
In this particular case, some shithead upscaled it like a moron, probably because he spends too much time at moe.imouto.org.
One thing you can do when you find an image like this is upload a downscaled image and this together, and make one the parent (the best quality one, which would presumably be the downscaled image). If you/someone can find the original that wasn't upscaled, that would be even better of course. :D
