This program allows to apply a choice of filters to any picture.
The user can choose the following options:
- exchange a red / blue / green part of the front picture by pixels from the background picture
- double exposure
- apply a filter in the shape of a given form (in the example it's horse).
In order to be able to use a picture of the user's choice regardless of the
image sizes in pixels, Image from PIL had to be used instead of SimpleImage.