when I’ve chnaged the color I did it this way, I don’t know how others do it
I completely back up the site using joomlapack
then instead of creating a whole new color, I take the default color for the template and change all of the images for the default setting to my new colors.
them I go into the template.css and change all of the css settings associated with the default color of the orignal to my new color of choice.
get used to using firefox’s firebug plugin, it will save you a ton of time finding all the files and lines of code that need to be changed
when changing any file, I make a backup so I can always get back to my starting point in case I mess up.
I do it via FTP and make a backup everytime I make a change. (you can use joomlaxplorer, but i think ftp is faster)
so, change the images and change the css, and keep checking to find all of the peices that need to be changed.