[NTLUG:Discuss] different colors in different netscapes

[lee@brave.com]

i created an image with the gimp and added that image to a web page. 
the background color image matches the background page color great with
linux netscape, but when i switch to view the page in netscape in
windows (either vmware or native windows), the colors don't match.  you
can see what i mean at http://researchtexas.com and
http://researchtexas.com/index1.html .

1.  why does it do this?

2.  how do i get the gimp to make exact color match with both platforms
of netscape?

thanks,

-- lee