On this page you can download the source of the images used by Green Chess. Some of them is from other place, others are my own work.
You are free to copy, redistribute and modify the images, only that you must Attribute and Share Alike (CreativeCommons).
The images of the standard chess pieces are from Wikipedia: Chess, slightly modified. The new pieces are mainly derived from these.
The boards are completely my own work, either by hand or with a program.
Many boards were created by the following C++ programs (command-line interface, C++11 is needed):
Different logos of the site: