Light changes things a lot also.
What airinhere was alluding to in blue backgrounds is that it gives you an indication of how much actinic light is being supplied to the mushrooms. I dissagree with airinhere that they are photoshopped if the backgroud is blue/purpleish (that is not always the case - definitely is sometimes). I keep mine under T5's and have had my tank very blue, my shrooms glowed, both the reds and greens. I have the same shrooms that J. Montgomery has above (he gave some to me) his daylights are MH, and they look sortof orangy red as seen above, but under heavy actinic T5's they glow a lot more.
So the lights that you keep them under can make them look very different from where you got them from.
I got a purple shroom from an LFS that is brigt blue under heavy actinics.
Craig