@triptych_angel -- it's not about saving for the web it's about working with icc color profiles which are different for shooting pictures and printing versus displaying on a monitors. i shoot all my pictures in adobe rgb however when i export to the web i have to change the color profile to Srgb as that is the color profile for monitors. check your editing program under preferences to be sure that when you are exporting for email and downloading that the color profile is Srgb and not some other color profile... know it is frustrating to have pictures appear one way on your own monitor and then differently on another... the disparity is usually because of color conversion not happening when images are exported through downloading or email because of incorrect icc profiles.
@cfrantz ah so that's why I'm noticing a difference lately. I used to save as SRGB but noticed the colours looked better on adobe rgb so started saving as that. Will change back.
@triptych_angel - another thought came to me have you tried emailing the picture rather than uploading and seeing if there is a difference? I have lightroom and I tend to email all my images to 365 and other sites where i could upload also email takes less time and I get to decide in lightroom the size and resolution of the print prior to sending. only downside is no exif info.
Oh well :) Will try that @cfrantz