User blog comment:Batran99/BANNER NEEDED 2017 Winter Staff Polls/@comment-32848605-20171125220837/@comment-15419758-20171125230357

I don't think Wikia is lowering your image resolution, but you're just trying to directly download it from your comment, which uses a thumbnail. Clicking "Open link in new tab" (not "Open image in new tab") gives the full 1920x1080 image. You should be using "Save image as..." on the full resolution image in the new tab rather than the comment thumbnail.