Pillow is a widely-used Python Imaging Library that adds image processing capabilities to your Python interpreter. It provides extensive file format support, an efficient internal representation, and fairly powerful image processing capabilities. Pillow allows you to open, manipulate, and save various image file formats such as PNG, JPEG, GIF, TIFF, and BMP. It is the friendly PIL (Python Imaging Library) fork that makes it easier for developers to handle images in their Python projects.