Okay those are some horrid pictures and like everyone else I don't see the difference.
However, I believe I know the issue you're referring to. The easiest way to see it is to find a foggy or discolored area in massm2 and make sure you have a crosshair on. You will quite clearly see a translucent box around the crosshair.
[EDIT]Okay I grabbed a quick screenie from massm2 to illustrate. Turns out it's not as simple as colored lighting/etc, so I'm not sure what causes it. It seems to be more visible in dark light, which obviously makes taking screenshots of it a pain. Also, when you fire (causing your immediate surroundings to light up a bit) it is more visible, indicating that perhaps the crosshair isn't taking into account the increased light level when rendering. But that's just idle speculation.
Anywho, here's the shot I got. Sorry about the gamma on it. The original screenie looked correct, then when I converted to GIF, the software I was using set the gamma way down for some reason, so I just bumped it up a bit. It's not pretty, but the problem is clearly visible.
