PIL stands for Python Imaging Library, which is a free and open-source additional library for the Python programming language that adds support for opening, manipulating, and saving many different image file formats. PIL was discontinued in 2011, and a project named Pillow forked the original PIL project and added Python3.x support to it. Pillow was announced as a replacement for PIL for future usage. Pillow supports a large number of image file formats, including BMP, PNG, JPEG, and TIFF.

Pillow provides extensive file format support, an efficient internal representation, and fairly powerful image processing capabilities. The core image library is designed for fast access to data stored in a few basic pixel formats. It should provide a solid foundation for a general image processing tool.

Pillow offers several standard procedures for image manipulation, including per-pixel manipulations, masking and transparency handling, image filtering (such as blurring, contouring, smoothing, or edge finding), and image enhancing (such as sharpening, adjusting brightness, contrast or color) .

To install Pillow, execute the following command in the command-line: pip install pillow .

In summary, PIL (Python Imaging Library) is the original library that enabled Python to deal with images, while Pillow is a fork of PIL that adds support for Python3.x and is the current library used for image processing in Python. Pillow provides tools for opening, manipulating, and saving many different image file formats, and offers several standard procedures for image manipulation.