Image when baking a normal map?

Hello everyone,
I was just reading the blender manual on baking a normal map from a high res mesh. To do this, I need to unwrap my mesh, but I don’t understand why I have to map an image to it for bake to work.
It seems to me that you just unwrap it, hit bake, and it should generate you a normal map. On the contrary, it says “No image found to bake to”. But when I load a random image, it works.

Just wondering why we need an image, and whether that image should be anything in particular.

Can someone please clear that up for me?

Thanks in advance!

No, you just need to add a blank image. My guess is that Blender needs to know the size you want the image to be (selected when you create the image in the UV/.Image window) or maybe it just needs the image as a memory place holder. Either way, just select New from the Image menu in the UV/Image window, while your object is selected and then bake should work.

I see, ok thanks!