Thanks so much Flemur. I am still working on the feh option.
Wow, people have exerted a lot of effort on image manipulation programs, but few do the seemingly simple thing I want. Zoom into a particular part of the picture and take a screenshot of that area. Sounds simple, doesn't it? I did not find any programs that can do it entirely from the terminal. Feh is probably the closest, but I am going to have to issue xdotool keystrokes to make it work. That doesn't sound right to me, but that is the way I am headed.
It just sounds so easy to supply an image file and a certain area of pixels to display, but I couldn't do it via the terminal. Surely Gimp can do it via their GUI.
It's possible Python Image Processing (listed below) can do this, but I need to research that further.
Anyway, I did a lot of research, so I guess I'll post some of that here for others:
Just a few Image Processing Options:
Feh - sure sounds like feh could do what I want, but it didn't work for me.
https://man.finalrewind.org/1/feh/
People having problems zooming with feh:
https://askubuntu.com/questions/1352729 ... fullscreen
Gimp Batch Mode:
https://www.gimp.org/tutorials/Basic_Batch/
GMIC (related to Gimp):
https://www.maketecheasier.com/advanced ... -and-gmic/
Python Image Processing - This has potential:
https://likegeeks.com/python-image-proc ... p_an_Image
fbi:
http://www.nongnu.org/fbi-improved/
PixInsight - This is a commercial product that sounds difficult:
https://pixinsight.com/resources/
There are plenty of others, but none I could find that would simply do what I want from the terminal.