I tried a "foolproof' package to root and flash my Nexus 7. It didn't work, and now my laptop will not "see" my Nexus at all, so I have some troubleshooting to do before I can view these images on i. We fools are so clever.
And now: "Starting with version 10 (released in September 2011), Adobe has removed support of JPEG 2000 from its Photoshop Elements software."
I guess I'll try ImageMagick, and see if it can convert these to 100% jpg.
Since "16 shades" apparently doesn't help on jpg, and doesn't work on some readers, and is far from ideal for other displays, it seems to me that approach can be, at least tentatively, set aside.
I personally want to continue to investigate the use of transparency with palette and grayscale pngs, since I think it could potentially be very nice in some cases.
My meager understanding of png says gamma is best left uninvoked.
My meager understanding of png says non-interlaced is preferable, if/when it matters at all.
I would add "dithering" to the options list, since I have a slider for that. Dithering, IMHO, should also be turned off.
I am surprised that using a web-safe palette is not an option that can be turned off in PSP. In PSE 10, at least for jpgs, it can be turned off.
I just now considered buying PSP X6 to play with these, but it seems to not have much market share, and also I came across this
security advisory from Secunia. So maybe later...