PainterTool has two types of photos.
A model photo is a photo of the subject you want to paint or draw. Model items are marked with light blue (cyan) color.
An art photo is a photo of your painting or drawing. Art items are marked with yellow color. These are also called sketch photos. An art photo is associated with a model photo. A model photo may have any number of art photos.
The main purpose of PainterTool is to compare the two and give hints where they differ.
Tap the collection button, which looks like nine squares, to slide open the collection view.
At the top you see your model photos. You can tap the blue plus-button to take a photo, the album button to fetch a photo from your album or the minus button to remove the selected model photo.
If you select a model photo, you will see its art photos, if it has any, at the bottom of the collection view.
Select a model photo. Then tap the right side of the screen to close the collection view.
Draw a few, light lines on a paper to mark the main features of the model. These will be used as guiding lines.
Tap the yellow plus button to take a photo of your sketch.
You can tap the Settings button, and then select edge detection to detect and view just the lines of the sketch instead of the sketch photo.
Make sure that the art layer is selected, and drag and pinch the art photo so it matches the model photo as well as possible.
Now you can see where your sketch differs from the model.
Tap the move-button to switch between moving and rotating the sketch.
When you are done, you can switch to the model layer, so you can zoom and move the photos simultaneously.
Make a few changes to your sketch, using the model photo and the guiding lines, and take a photo of the improved sketch.
Continue with improvements until you are satisfied.
Now the proportions are correct. Now you can begin creating some art, adding shadings and a personal touch.