This application is a little Digital Image Processor (DSP).
Starting from an image, it tries to detect the image contours, i.e. the border lines between darker and lighter areas.
It then creates a new image with these lines, looking like a pencil drawing derived from the original picture, and shows it on the screen.
The main menu lets you choose where to get the original picture from: or an existing one, selecting it from the iPhone photo album, or a new one, shooting it with the internal camera.
When the resulting drawing is shown, you can save it in your photo album: just tap on the screen, and a popup window will give you the choice to save or discard it.
If you choose to save it, a short sound will notify you when the recording completes.
Be aware that the effect of the resulting drawings is not granted to be always pleasant and homogeneous, because it strongly depends on contrast and sharpness of original pictures.