Dark pics and webcam images

I am at my wits end with this issue. All my pictures are dark and so is my webcam. These images are only dark to me (including the cam) and not to other people viewing them. I tried using another viewer such as irfanred but it didnt help. Everything i view onthe internet is fine as are pictures i save (including e-mail pictures). I am possitive it was a setting I changed when I first installed XP on my computer that was a customisation to my eyesight and now I cant find it. This has been a issue for me for well over 9 months or so and is very frustrating. So bad to the point that i think my only solution is to format my computer(yes drastic ,I know). Worst effected pictures seem to be digital photos but its not my camera either as I have had pictures that were put onto a cd of my fathers from his computer and they are also very dark on here. If anyone can help me it would be greatly appreciated.

 

Adjust the Gamma correction/brightness of your monitor, in control panel, display properties.