Thanks for the attention to this!

I went back and tried and, ..., hmmm, it works for one pic at the time. But for multiselect the rotation ability disappears.
For more than a few portrait pics it's faster to rotate in some other program as I did.
I suggest the rotation function takes multiselect (and single) and is available in the Images drop down menu - where I expect all image related functions to be found. (I also tried right clicking an image (and images) but nothing there. Not that important. Just tried.)
Your ref. addresses problems to interpret rotation info correctly. It doesn't mention any ambiguities how rotation is marked up.

I used to use Porta to produce albums. It's built on Simpleviewer. It does rotation correct. (Haven't tried all 8 positions. Just 3 or 4). Irfanview is another which I use and does the job. I suggest it's added to Juicebox as well.

Another thing, for conveniance I suggest a album/gallery default directory is <location-of-pics>/album (or a synonym) and that it is created by Juicebox when I accept the suggested name and location. A warning for an existing non empty directory.