I am hoping that someone here collects computer images from days gone by. Many years ago when I used my ATARI-ST I made two drawing I believe I used the art program NEOCHROME, or possibly DEGAS. The first one was a picture of a 3D ROSE on a light blue grid-like background. The other one was the same type background with a 3D teddy-bear. I have been looking for these for a while with no luck. I made these during my days when I worked in a computer store and sold ATARI-ST, AMIGA, and the 8 bit line of commodore & Atari computers. I put my pictures out in the domain on "Bulletin Board Service" (For you kids, that was pre-Internet). During an Atari convention they had a slide show of pictures and My Teddy-bear was used. Kinda cool to see your work being selected by the company that made the computer. Just hoping to see those pictures again. :)
Looking for either
"rose.neo" atari or
"rose.pc1" atari in Google images with an exact requested size of 320x200 yields this result, which seems to match your description pretty well.
Could it be that one?
Here is a better version from Demozoo.
The original Neochrome file can be downloaded from this page.
As it happens, I have my own archived copy of the STe Discovery Xtra Language disk here. Here's ROSE.NEO:
I've screencapped all of the Neochrome images I have on this disk and put them on Imgur: https://imgur.com/gallery/bjs5OTC
That's perhaps the full original set from that disk; I guess I was careful with preservation even when I was a teenager. No bear on there, though!
If you want the full set of what I have, try: https://sdstrowes.co.uk/misc/atari/discovery-xtra-neochrome/
Note that at least the waterfall was "animated" thanks to some neat colour cycling. NEOSHOW.PRG shows off the animation. Probably this is one of those things where this is technically still copyrighted by somebody. Happy to take these down if somebody sends me a nastygram.