DiffusionBee is a free tool for generating AI art on your computer using Stable Diffusion technology. It includes various features such as text-to-image generation, image modification, in-painting, out-painting, upscaling, and the ability to use custom models. It also has advanced options for power users and all generation happens locally, without any data being sent to the cloud. There is also an active community on Discord where users can ask questions and get support.