To do with the jpg cards, though some of you have already probably used this so see it as a recommendation for those who're new to the wiki and would like higher quality cards, I recommend waifu2x.
Although a rather distasteful name/url, it's a site that'll reduce the noise and make your pictures clearer, it'll also upscale, though I recommend keeping it on a low reduction setting if you're upscaling 2x. This'll work for both cards and icons on the wikia, so go wild.