Capture camera image > draw on image > save/share image

Hello, I need to figure out a way to capture a Unity camera image on Android, draw on the image using the finger on touch screen, and then save/share the image. I think I already have a method for saving and sharing, but I need to figure out the best ways to:
1. Capture the Unity Camera image to a still 2d image on Android.
2. Draw on the captured image using the finger on touch screen, with color and width controls.

Does anyone know of Unity Plugins that take care of some of this? (Preferably free.) Or, can anyone lead me in the right direction, particularly for the drawing part?