If you mean a splash screen, I suggest starting in windowed 640x480 mode and loading an image into bitmap 0, or loading an image and pasting it.
Either:
LOAD BITMAP "Title.jpg",0
or
LOAD IMAGE "Title.jpg",1
PASTE IMAGE 1,0,0
SYNC
Don't do too much if your using windowed mode and having to change the resolution, once you change the resolution you'll often have to re-load the media.
If you don't want a splash screen, the same commands apply, except you might want to look into sprites instead, you can stretch a sprite over the whole screen:
LOAD IMAGE "Title.jpg",1
SPRITE 1,0,0
SIZE SPRITE 1,screen width(),screen width()
SYNC
`Wait for a keypress
SUSPEND FOR KEY
`Tidy up
DELETE SPRITE 1
DELETE IMAGE 1
You just got to find a way that suits your program best, personally - I'm more likely to go for a 640x480 window with display options etc, then change the resolution and colour depth before running the program properly.
HTH,
Van-B