I've taken some screencaps using the 'Snipping Tool' from Windows 10. When I open the jpgs in PS, the image has ghosting especially around the text.
I am looking at the images in PS @ 100%
I don't recall having this problem in previous versions of PS.
After the situation in various software, it appears the Snipping tool does not visually illustrate what it is going to be saving in the JPG format. (Perhaps it applies a low-grade compression to JPGs that are unapparent until after you try viewing it elseware.)
The solution was to save the cap as a PNG, and work from there.