Thanks - that gets half way there in defaulting to the correct paper size at least ;-). So the next request would be that it remembers the orientation - whilst Portrait is a sensible default for the printer system-wide, a lot of graphics tend to be more landscape-oriented.
Of course, better yet, it should make an intelligent guess based on the image dimensions, and choose automagically: if the image is more landscape, default to that; and vice versa. (This is the behaviour of the built-in Paint.NET printing dialog, by the way...)
Cheers,
Rob