Colour matching, dreamweaver/Photoshop CS5

Question

I'm trying to match colours used in Dreamweaver and PS CS5, so that if I make a faux background using Photoshop, it is the same colour as the colour I use in Dreamweaver.  For some reason, even  if I use hex codes, the colours look different when I preview in a browser.
Also, I can't use the PS CS5 eye dropper tool to sample colours outside of Photoshop. As soon as I move the eyedropper tool outside of the PS workspace, it becomes an arrow pointer again.
Can anyone advise where I'm going wrong?
Thanks
Sally

Answer 1

GIF for line-type graphics with limited colors
JPEG for photos or other rich complex graphics
PNG-24 for graphics with alpha transparency (masks)
Then it's a matter of selecting what file-size and optimization you're looking for.
Smaller equals faster but small can also mean lower quality (less colors for GIFs, more compression on JPEGs).
And turn off "save as sRGB" in Photoshop unless you know how to use color profiles and use color management systems.
For even more color madness: Some browsers support color profiles, Safari being one of them, whereas previously, web graphics didn' even include color profile metadata . This meant your computer just had to take a best guess at what color to display and which is why the 256 web-safe colors became such a huge thing - because at least those colors displayed well regardless of which computer or screen you were using. This is now no longer a problem as most displays support sRGB color space which is kind of a "lowest-common denominator" color space profile.
Anyhoo... that's probably more information then you need. Hope its interesting and useful.