Chris, I still have no idea what you are talking about.
What format is the image that you purchased? Any number of regular graphics software programs can convert image files from one format to another including several free ones (paint.net, GIMP, etc). And Photoshop certainly can convert between formats.
But what do you mean when you say that you want to "make it fit on a standard DVD"? A "standard" DVD can hold 4.7 GB. Is the file larger than that? If so, then you need to use software to make it smaller. And then you can copy/burn it to a blank DVD."
But it's not clear what you are trying to do by "making it fit on a standard DVD".