Adding custom sets of colors to the Garland theme for Drupal

You can ad custom color sets to your copy of the Garland theme by editing the file color.inc located under your sites/all/themes/yourgarland/color directory. To obtain the appropiate set, you can first select the values using the custom option and use the values later on the file. A very good way to get an approximation of the correct colors is to extract them from a picture that you feel is representative and use a resource like the Color Palette Generator to extract the main colors.