picture into graph diagram thing

[urbanchic1212]

ok so i have this great idea for my birthday cake I'm gonna make a ton of cupcakes and i want to make them look like a picture but i don't know how to get my picture into like a graph so i can use that to go off and was wondering if any of you quilters know a site that can do this I found one for needle point but its too complicated. I'm only going to be using black and white as the colors so it'll be pretty simple any ideas anyone?