[Steven W]

POV-ray

https://www.povray.org/

Thing been around forever. You can even find old versions for DOS, OS/2 and Win3x at that site. Not the easiest thing to use...

[Steven W]

XnView

https://www.xnview.com/

You may have noticed this in my Raspberry Pi screenshot, it makes me miss Irfanview a little less on Linux. There's a Windows version too, if the MP (multi-platform) version runs a bit flaky on Windows, check under "Products" on the site and get the 'Classic' version. Oh yeah, I think it was version 1.50 that works on Windows 3.x.

The more I learn to use this on the Linux box, the more I am grateful that Pierre Gougelet makes it available. This thing fills in some gaps and does some things better than various proggies and command-line utilities do.