DrawShield offers some control over the visual appearance of the shield image. The options for this can be selected on the main "create" page by clicking on the "Drawing Options..." button, this brings up the following, which I hope is self explanatory.
Note that if you change any of these options (and have cookies enabled) then your choices will be preserved between sessions. You can safely disallow cookies for this site if you do not want this behaviour.
In addition to setting options using the form there is also a facility to specify these options by a (non-standard) extension to the blazon itself. These are described in detail on the Drawing Options Extension page.
Providing Your Own Palette
Palettes are simple text files consisting of the tincture name, an equals sign and a hex code, one per line with no whitespace. If you have a palette that you would like to have added just e-mail an appropriate file to me. The default tinctures are provided below as an example, cut and paste this into your own file and modify as required. Any tinctures not given will be drawn using the DrawShield default colours.