So I am an advanced novice user of Photoshop and have begun doing a lot more digital painting as of late. When I paint in black/white/gray in Photoshop I can get a good scale of values from light to dark...however, when I save the file as a .jpeg copy to post here at this site, the copy goes really dark and a tad fuzzier.

I can tolerate fuzzy, but the dip into the darker territory is really bothering me...does this have to do with the quality of the .jpeg copy saved, the number of scans, etc., or is this just "the way it is?" Or should I adjust my values in the .psd file before I save it as a .jpeg to overcompensate for this?

Any info or ideas or experiences in this? Having originally been exposed to Photoshop in its 2.5.1 incarnation waaaaaay back in the 1990's, CS is a whole new ballgame...