Stable Diffusion 3.5 / SDXL (open source) Review (2026)

Stable Diffusion 3.5 (Large and Medium) and the still-popular SDXL ecosystem remain the foundation of open-source image generation in 2026. With ComfyUI, Automatic1111, Forge, or Fooocus on a 12–24GB GPU, you get full pipeline control: ControlNet, IP-Adapter, LoRAs, regional prompting, and tens of thousands of community fine-tunes via Civitai and Hugging Face. Output ceiling is below Midjourney v7 and Flux 1.1 Pro, but the flexibility, privacy, and zero per-image cost are unmatched. Stability also offers a hosted API via Stability Platform, plus tools like Stable Image Ultra for users who want SD without the GPU. Best for: developers, technical artists, and teams that need self-hosting, custom fine-tunes, or full creative control.