How it works
A diffusion model learns to remove noise from images. To make a picture, it starts from random noise and cleans it up step by step, guided by your text prompt, until an image matching the description appears. Stable Diffusion does this work on a compressed form of the image, which is what made it light enough to run on a home graphics card.
What changed the field was access. The model weights were released for download, so people could run the model privately, study it and build on it. A large ecosystem followed: interfaces such as ComfyUI, small add-on files called LoRAs that teach a style or a face, and control tools that fix a pose or a layout. There are several generations of the model, and each has its own strengths, hardware needs and license.
Creators meet Stable Diffusion when they want control that hosted image services do not offer: a consistent character, a specific pose, private generation or a custom style. The cost is setup and hardware. The license matters as well. Stability AI's current models are free under its community license only below a revenue threshold, and other model families such as FLUX now compete with it, so check the terms of the exact model you download.
A worked example
A creator wants the same illustrated mascot in ten different scenes.
- Install an interface such as ComfyUI and download a Stable Diffusion model whose license fits the intended use.
- Generate candidate mascots from a prompt and pick one.
- Train a small LoRA on images of that mascot, so that the model can redraw it.
- Generate the ten scenes with the LoRA loaded, and fix poses with a control tool where the prompt alone is not enough.
An illustration, not a real account. Any numbers in it are made up to show the method, and are not benchmarks.
Common mistakes
- Confusing the model with the interface. Stable Diffusion is the model. ComfyUI and similar tools are programs that run it.
- Assuming open means free for any use. Each model version has its own license, and commercial terms differ.
- Using a real person's likeness without permission. A model that can copy a face does not make it lawful or fair to do so.
Questions people ask
Is Stable Diffusion free?
The models can be downloaded at no charge, and you pay for the hardware or cloud time to run them. Commercial use depends on the license of the specific model. The sources on this page give Stability AI's current threshold.
What do I need to run Stable Diffusion?
A computer with a capable graphics card, or a rented cloud GPU. Requirements differ a great deal between model generations, so check the model's page before you buy hardware.
Should I use Stable Diffusion or Midjourney?
Midjourney is a hosted service that is easy to start with. Stable Diffusion takes more setup and gives more control, including custom training and private use.
Sources
The research paper behind Stable Diffusion. It applies diffusion models in the latent space of pretrained autoencoders to cut the computing cost.
arXiv (Robin Rombach and others): High-Resolution Image Synthesis with Latent Diffusion Models 20 December 2021
As of October 2026, Stability AI offers its Community License free to researchers, developers, small businesses and creators with less than $1M in annual revenue, and requires an Enterprise license above that.
Stability AI: License read 13 October 2026
Every link was opened on 13 October 2026. Products and policies change, so check the source before you rely on a figure.