he wanted to know the right way to do it and was advised how. Thats the point of learning, right?

Its fine to do it however you choose and true, it may work for you.

Why not just take the extra .1 second and click the box?

Actually, a more correct way would be to increase the canvas size and then paint the new area around the picture black/white.

But hey, do whatever you want, honestly. Its not that big of a deal.