Stable Diffusion is an open-source AI image generation model developed by Stability AI that has become the foundation of the open-source generative AI movement. Unlike closed-source alternatives, Stable Diffusion can be downloaded, modified, and run locally on consumer hardware, giving users complete control over their image generation pipeline without per-image costs or content restrictions.
The latest Stable Diffusion XL (SDXL) and SD 3.5 models produce photorealistic images with improved coherence, better text rendering, and support for various aspect ratios. The open-source ecosystem includes thousands of community fine-tuned models, LoRAs for style transfer, ControlNet for precise composition control, and tools like ComfyUI and Automatic1111 for advanced workflows. It supports inpainting, outpainting, img2img transformations, and upscaling.
Stable Diffusion is free to use locally with your own hardware (requires a GPU with 6GB+ VRAM). For cloud access, Stability AI offers an API starting at $0.01-0.03 per image, and DreamStudio provides a web interface with credits starting at $10 for ~5,000 images. The model is available under permissive licenses allowing commercial use, making it the go-to choice for developers, artists, and businesses building custom image generation solutions.