The rules say that we can use whatever type of generator. Can we use a generator for:

2d images, such as characters, props, etc?

Audio? 

For audio I'll definitely be using programs such as SXFR and Bosca Ceoil. Those are two great audio generators I've been experimenting with.

I believe 2D generators are fine as long as you can do what the rules say and have some control over the output it generates.