SketchBook

The application provides a clean and clear canvas, with tools at the top for picking from different brush and pencil sizes, as well as colors. You can create multiple layers in your project and import pictures stored on your phone. It lets you adjust the size of images and even draw on them. You can also use multiple symmetry tools and draw shapes in different styles.
 
Aside from importing images from the camera roll, gallery or Google Photos, you can also add text to a layer, cut, copy or duplicate certain sections. It comes with opacity, brightness and blending tools as well. Moreover, you can zoom in 2500% on your images and use gradient fills tools, like linear and radial.