Are you saying so in looking at them from another computer? If not, its good to check the photoshop format, if you did any lab work, or you may even have to fiddle with the color adjustments on a format other than the one you used, or even check the color on your display - which outside of basic monitor tests or acquiring a specific ICC profile , could bring you to invest in an optical calibration device that does virtually everything for you at the touch of a button. For what its worth, I don't believe it is your monitor, but if the pictures are dissatifying (and I like them...)then you can fiddle with taking your photo through a camera raw converter image editor, test different variations, and see what you come up with when you try to post it on a web page, possibly if you use an online storage site like Photobucket.
kvasir: i looked from the same monitor. they changed once uploaded. it only happens sometimes... i use the same color profile settings, same res. and size.