Hi Digi,
Photoshop uses a predefinited RGB setting decided during install time. This could be your problem (that usually is not intended to be a problem :p ); if you want to see the images with your RGB monitor setting (and thus the way you'll see them in a browser) you have to search for the preview submenu (I don't know the exact name in localized versions, mine is under 'visualizza') and choose the option 'no compensation'. You could also preview a standard Mac or Windows RGB setting and as you post images on the web you should find the best compromise between all of them assuming that your monitor gamma is set correctly... Gamma things...
