You can e.g. specify some great looking 8-color images for several buttons of your application and MUI will ensure they look fine even on 4-color screens or on screens with completely different colors.
When running Kickstart V39 or higher, MUI will use ObtainBestPen() to find or create your colors. Below V39, a simple color-map search is performed to find the best matching entry, but no colors will be changed.
The source palette is specified with an array of ULONGs, three entries per color, 32bits per gun.