Stable Diffusion 3.5 is the open-weights standard for anyone who wants to own their image pipeline. Released in October 2024 after Stability’s restructure, it remains in 2026 one of the two go-to open base models (alongside FLUX.1 [dev]) for running locally on your own GPU — where the marginal cost per image is effectively zero.
The family ships in three sizes: Large (8.1B parameters, 1-megapixel quality), Large Turbo (a distilled 4-step variant for near-real-time speed), and Medium (2.5B, tuned to run on consumer hardware). All are available under the permissive Stability AI Community License — free for individuals and businesses under $1M in annual revenue. If you’d rather not self-host, Stability’s API exposes them as Stable Image Core and the flagship Stable Image Ultra.
Its deeper advantage is the ecosystem: fine-tuning, LoRAs and ControlNet give control no closed model offers, with Civitai as the community hub. The honest trade-off is that default quality and prompt fidelity trail hosted leaders, and good local results take setup and a capable GPU. It rewards teams that value control over convenience.
Best for
- Privacy-sensitive or offline generation
- High-volume generation at near-zero marginal cost
- Custom fine-tunes, LoRAs and research
Pros & cons
Strengths
- Free to run on your own GPU after hardware cost
- Full control: fine-tuning, LoRAs, ControlNet, ComfyUI ecosystem
- Three sizes (Large 8.1B, Large Turbo, Medium 2.5B) for any hardware
Limitations
- Out-of-the-box quality trails hosted leaders like FLUX.2 and Imagen 4
- Requires setup and a capable GPU for local use