Would you provide a generic XCF so people can colour this as they wish?
Also, the wallpapers do like rather nice, I may be half-tempted to use one of the pre-existing ones, but people have different themes and stuff, they might want a red one, a pink one, a yellow one etc. and gimp just lets people do that, but XCFs make things way easier because people can then do weird and wonderful things without having to fuzzy-select and cut stuff.
i would if i could get it to upload. Sorry, the file you are trying to upload is not authorized (authorized extension: jpg, jpeg, png, gif, ico, svg, xcf.bz2, xcf.gz). put the last extentions xcf.bz2 and xcf.gz still will not upload.
Just use a free service to upload. http://mega.nz, despite it’s heavy emphasis on security gives you 50GB of online storage for free so that should be more than enough room for all of your future works.