Fly is a C program that creates PNG, JPEG or GIF images on the fly from CGI and other programs. Using Thomas Boutell's gd graphics library for fast image creation, it provides a command-file interface for creating and modifying images.

The original program, written by Martin Gleeson, is now supported on all unix-like systems. We propose a deep refactoring of the application, moving towards a more efficient, safe and easy-to-expand solution for comfortable future development.

This new version of the Fly program has been developed as final project for one of the exams in the computer engineering master's degree program at University of Pisa.