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:
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 ...
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.