When I save a picture it makes the colors darker...

I made a picture, and was testing scanline technique on it, when I was done I saved it and uploaded it to a website so I could use it as a sig. Well when I viewed it, it was much darker than it was in Adobe. Anyways I did some searching trying to find out was going on and havent had any real luck accept for I think it saving under my monitor colors, even though I set it for ColorMatch RGB (least I think I set it.) Anyways any help would be greatly appreciated

Ok, been messing around with it some more and I think I have discovered my problem. When I save, it saves it using monitor colors instead of Adobe RGB colors. So what I have to do to get the right colors is going into my monitors color mangement and select Adobe instead of what I had. Now this doesnt take long for me, but is there just a way to set Adobe to save using Adobe RGB colors instead of my monitors?