How do people write on photos?

I am looking for an app where I can actually use my own finger to write or draw on any of my own photos. Not a text app but one where can I can do handwriting of any text message directly on the picture. I should also be able to scribble or scratch out a face or body in the photo, and adjust the line thickness for scribbling mode or just drawing my own text messages directly on the picture.

The app "Write On Picture" is shown in the screenshots below. You can use blot mode to quickly scribble out a face or blot over someone in the picture. Change the color or writing style to use your own handwriting messages when drawing on the picture.