Graphics

Biggles
A 2D scientific plotting package for Python, geared toward the production of publication-quality plots. [Open Source, GPL]
http://sourceforge.net/projects/biggles/

gdmodule
Python support for GD graphics library. [Open Source, BSD-like]
http://newcenturycomputers.net/projects/gdmodule.html

Gnuplot.py
A Python interface to the gnuplot plotting program. [Open Source, GPL]
http://gnuplot-py.sourceforge.net/

JpGraph
An object-oriented presentation graphics library. [Open Source, GPL]
http://metagram.webreply.com/

Lightflow Rendering Interface
The Lightflow Rendering Interface is an object oriented programming interface to synthetic rendering, which provides a common environment and description language to treat light distribution in three dimensional spaces. Also provides a Python API to the renderer. Free for non-commercial use.
http://www.lightflowtech.com/

The MayaVi Data Visualizer
A free, easy to use scientific data visualizer. [Open Source, GPL]
http://mayavi.sourceforge.net/

Ming
A C library for generating SWF ("Flash") format movies. Ming includes a Python wrapper for the library. [Open Source, LGPL]
http://www.libming.org

PyChart
A Python library for creating high quality Encapsulated Postscript, PDF, PNG, or SVG charts. [Open source, GPL]
http://home.gna.org/pychart/

PyOpenGL
The binding layer between Python and OpenGL. [Open Source, BSD-like]
http://pyopengl.sourceforge.net/

Python Computer Graphics Kit
Modules for creating 3D computer graphics images, focusing on Pixar's RenderMan interface. [Open Source, BSD-like]
http://cgkit.sourceforge.net/

Python TWAIN Module
Provides an interface to the Microsoft Windows TWAIN sub-system. [Open Source, GPL]
http://twainmodule.sourceforge.net/

PythonWare Image Library (PIL)
Provides image processing functionality and supports many file formats. [Open Source, BSD-like]
http://www.pythonware.com/products/pil/index.htm

VideoCapture
A Win32 Python Extension for Accessing Video Devices (e.g. a USB WebCam, a TV-Card, ...) [Open-Source, LGPL]
http://videocapture.sourceforge.net/

VPython
A free, open-source module for producing real-time 3D scenes with Python. Includes a modified version of IDLE. [Open Source, BSD-like]
http://www.vpython.org/