You cant do anything about it, the default gamma in OSX is stupidly bright, which lightens and washes out images compared to normal gamma.
You dont have to worry about it if you are using a Mac, your images should look better on Windows with 2.2 gamma since practically everything looks better with 2.2 gamma. If youre in windows then you might want to temporarily brighten your image to check for weird artifacts in the dark areas since they may show themselves with OSX's brighter gamma.
I think only iMacs and Apple monitors have this problem though, third party monitors should use a color profile with 2.2 gamma as default, Im pretty sure my Dell 2005FPW did.