LoadTheme             FILE=FROM, APPLYPALETTE=AP/S, APPLYFONTS=AF/S,
                      APPLYBACKGROUNDS=AB/S, APPLYSOUNDS=AS/S

This command is similar in function to the Load Theme menu item in the
Settings menu.

The various APPLY.. switches allow you to choose what the theme will affect.

For example, APPLYBACKGROUNDS will only load in new background images.
Fonts, sounds and the palette will remain as they are.