Thanks, Stamper and Les.
I think I shall note that if by the "four images" you have in mind the four Yellowstone (predominantly orange) shots I posted in the reply #106, it is fair to say that they should look identical to you, simply because they are a single png screenshot, converted to jpeg (to reduce file size), and as such can not possibly show the difference. As a single shot, you therefore can not differentiate between embedded and non-ebedded versions.
If, however, by the "four shots" you have in mind the two of the red sky photos (post #92), plus the two of the Yellowstone ones (post #93), than you would be in the position to compare them, as each pair contains one embedded and one non-embedded jpegs, directly coming from PS Save for Web.