I want to burn image of homemade dvd

I have produced a homemade DVD using DVD studio pro. I can burn dvds that play on a dvd player but would like to keep an 'image' of some kind that would allow me to burn further copies much more quickly. I have tried the apple .img file but when burnt using disc utility it soe not sem to play on a dvd player. I am sure these is easy with idvd but I cannot get it to work with studio pro. Please help