This is an original background based on: https://www.dreamstime.com/beautiful-sand-desert-background-landscape-desert-background-landscape-mountains-image123663070
Made in Photoshop CS6 based on an 8 x 8 pixel grid.
Background generated by Floating Muncher: https://floating.muncher.se/bgrip/bgripper.php
This is a fun thing to do to replicate or adapt photos, so did edit1754.
Credits to the respective authors of the photograph.
I'll have to reject this due a serious issue.
While it's a nice attempt of doing a realistic background, the main issue here is that the mountains and the sand are hardly dinstiguishable at all, they blend so well that the background ends becoming flat. I suggest distinguishing both. As for the mountains themselves, they don't look convincing enough like the photography it's based on, it's lacking the dark shade that the original has.