I would say the sam8 is the 8 and the sam3 is the 3
Reason:
Overall shinyness or gloss that pervades the image. I have seen this on a lot of images I have, although only screen viewed there is a depth and fullness of the image that takes you there.
Although I may be wrong on this one it has the same characteristics.
Not long ago I was shooting a lot of 5 mp images to save room on the cards, these were mountain shots with an exuberance of colour and light. 5mp seemed the way to maximize the shots, and I also had gone to fine from superfine.
Big mistake, now while scrolling through, there are some 7mp supers in there, made for scenes I really wanted (lucky) with a whole string of 5mps fines. The difference is staggering, although without the 7's the trip through the mountain would be delightful, when hitting the 7's supers, they pop out like WOW.
I did some research and some indication was that there would be little difference, and with some post processing I'd say they could get there, but for me there is a need to be there (7) as much as possible. Unfortunately it required more cards etc to get the shots home.
Regarding size, raw at 7 is reported 7 meg images would be normal, with my Jpgs, &supers many are at 6.5 indicating little compression when the scene is complex. I would go raw if the frmat was more user friendly, but for now the camera is stuck on 7mp superfine.
s70 18,000 pics so far 10% at 3mp 15% at 5mp 80% at 7