So… I thought that I had figured out what the problem with the non-displaying pictures was, but then I purchased a fruit-based tablet and was horrified to see that apparently even the .jpg and .gif images from Google+ are not displaying in the Apple browser.
I confess that I’m pretty amazed that at this level of maturity of the web that there is so much content incompatibility. I thought we had gotten beyond that YEARS ago. Apparently I just wasn’t working with publishing enough.
In any event, I’ll try to only use .jpgs and .gifs from external web sources and only venture into Google+ for the animated stuff (which appears to display okay).