I love the various textures in the banner, and all green is another good one for Christmastime! Beautiful banner, and it looks fine to me as is.
If you just connect your phone to your computer and copy the files from the phone directly to the PC, there shouldn't be any change at all in the quality. It should transfer the same exact image in the same exact format. If you're using some special software to transfer from phone to PC, that's probably what's causing the issue, and there's zero reason to be forced into using any extra software just to transfer files over.
