photoshop cs2 problem

[srs]

images i work on in photoshop, look great, then when saved and sent as either emails, or uploaded to site, always look consistently lighter in tones then what was in photoshop....use same monitor for all viewing....big time problem...work is always b+w...is setting or some other simple thing...any help appriciated??

[another view]

Are you using any different color spaces (as in Adobe RGB)? This can amount to a difference when looking at the file in the sRGB color space.