I see a lot a creativity here with people making lots of wallpapers, this is brilliant If you want your wallpaper to be considered for inclusion in Ubuntu MATE then the minimum resolution is 1920x1080
Additionally you should give your wallpaper a tile, and clearly state that it is licensed under Creative Commons (CC-BY-SA) so we can correctly attribute copyright.
I apologize for being dense, in regards to your much appreciated note here. I understand the minimum resolution part; but may you (or anyone else) please glean over the procedures involved in the second half of the posting?
You just need to state in the post containing the wallpaper that said wallpaper is “Licensed CC-BY-SA” and that means I can include it in Ubuntu MATE