I'm very confused by this and hopefully someone will be able to shed some 
light.

I'm preparing some graphics for a webpage. The background colour of the 
page is #CCCCCC which I believe to be from the web safe pallete. I have 
both a gif and a jpeg saved with the PS save for web function. Both these 
optimised images have #CCCCCC as the background colour when viewed in PS

When I display the page in the browser (IE5) things go wrong.... I can see 
the outline of the .jpg. When I take a screen shot of the browser display 
and paste it into PS I see some strange results.

The background of the page is actually made up of alternate pixels of 
#CFC8CF and #C0C8C0 !!??!

The background of the jpg is displayed as #CFC8CF which makes it visible 
against the background.
The background of the gif is displayed as alternate pixels of #CFC8CF and 
#C0C8C0 which merges it with the background even if it is the wrong colour!

Nowhere in the browser display can I see #CCCCCC which I really cannot 
understand.

Am I just missing the whole point with web safe colours?