Using hand drawn graphics in slides

Hand drawn graphics can work great together with images in slides. As an example, see these ads below. (I am not sure whether these ads do a good job in selling markers, they are great though in warning you to take care of your health).

It is possible to draw shapes using a mouse or a drawing pad in PowerPoint, but I always find it hard to replicate that marker effect. Instead, I scan in real hand writing using a scanner, and then kill the white background with the Photoshop color range filter.