how big does an image need to be?

so i have never done a dvd menu before and i am taking a image i made from photoshop for the background. i just need to know how big does the image have to be so it won't lose quality?

thanks,
keaten

It needs to be the full resolution size of the frame size you are using. DV is 720 x 480 pixels but using a Photoshop image needs to take into account square pixels used in video rectangular pixels.

also everything is widescreen. i am a little confused on to what size the image actually needs to be in photoshop so it won't lose resolution at all. an actual dimension would be perfect. thanks for the help.

when i put the image in dvdsp it looks all smooshed. yet when i put another image in that one is fine. but i don't want that image! help?

keaten