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Stable Diffusion

by Stability AI
Free Image Generation
★★★★½ 4.6 (7,200 reviews)

Stable Diffusion is the world's leading open-source image generation model. Run it locally for free with no limits, or access it via API. A massive community has created thousands of fine-tuned models for every style imaginable.

How to Get the Most Out of Stable Diffusion

Run Locally for Unlimited, Private Image Generation

Install Automatic1111 or ComfyUI on a machine with an NVIDIA GPU (8GB+ VRAM recommended) — both are free and actively maintained. Once set up, you generate images with no usage limits, no per-image cost, and no data sent to external servers. For designers or developers generating hundreds of images per day, local Stable Diffusion pays for itself within weeks compared to cloud API costs.

Use ControlNet to Maintain Composition and Pose

Install the ControlNet extension in Automatic1111 and load an OpenPose or Depth preprocessor. Upload a reference image to extract pose or depth data, then generate new images that maintain the exact composition while changing style, subject, or setting. This level of compositional control is unique to Stable Diffusion — you can generate a character in the same pose as a reference photo without using the reference image's content or likeness.

Fine-Tune a Custom Model on Your Own Subject with LoRA

Use LoRA training (available via tools like Kohya_ss) with 10-20 photos of a specific subject — a product, a person, a location, or an art style. Train a custom model that generates your subject consistently in any context. Product photographers use this to place their items in any setting; brands use it to generate marketing images featuring their specific products without a photo shoot.

Our Take

Stable Diffusion is the right choice for users who need unlimited generation, maximum customization, or complete data privacy — no other tool offers all three simultaneously. The technical setup barrier is real but manageable; once running, the workflow flexibility through extensions like ControlNet and LoRA has no equivalent in commercial tools. For users who want strong results without technical overhead, Midjourney produces better out-of-the-box image quality. Stable Diffusion's true power is for developers and power users who want to build on and customize the model, not those who want a polished consumer product.

Frequently Asked Questions

What is Stable Diffusion and is it free?+
Stable Diffusion is an open-source AI image generation model developed by Stability AI that you can download and run for free on your own hardware. Unlike cloud-based tools like Midjourney, Stable Diffusion requires a computer with a compatible GPU (NVIDIA recommended, 8GB+ VRAM) and technical setup using interfaces like Automatic1111 or ComfyUI. There are no usage fees for local deployment.
What GPU do I need to run Stable Diffusion?+
For comfortable local generation, an NVIDIA GPU with 8GB VRAM is the recommended minimum — cards like the RTX 3060, RTX 3070, or RTX 4060 Ti work well. 6GB VRAM is possible with optimizations but slower. AMD GPUs are supported but require additional setup. Systems without a dedicated GPU can run Stable Diffusion via CPU but generation times are very slow (minutes per image).
How is Stable Diffusion different from Midjourney?+
Stable Diffusion is open-source, runs locally (free, private, unlimited), and is highly customizable through extensions and custom models. Midjourney is a cloud service with no local installation, produces more polished artistic results out of the box, and is easier to use. Stable Diffusion is better for technical users who need privacy, customization, or unlimited generation; Midjourney is better for users who want the best artistic results with minimal setup.
What is a LoRA in Stable Diffusion?+
A LoRA (Low-Rank Adaptation) is a small fine-tuned model that modifies Stable Diffusion's output to incorporate a specific style, subject, or character. You apply LoRAs in your generation interface by including the LoRA trigger word and weight in your prompt. Thousands of community-created LoRAs are available on CivitAI for art styles, specific subjects, and aesthetic modifiers.
Try Stable Diffusion Today
Open-source image generation for everyone. Free to start — no credit card required.
Visit Stable Diffusion →
Opens official website · Free · 2022 · 10M+ users
Pros & Cons

✓ Pros

  • Completely free and open source
  • Run locally with full privacy
  • No content restrictions
  • Thousands of custom models
  • Highly customizable

✗ Cons

  • Requires technical setup for local use
  • Less consistent quality than Midjourney
  • No official support
  • GPU required for local use
Pricing
Free Plan
Yes — completely free and open source
Paid Plan
Cloud API pricing varies
Who Is It For?
✓ Best For
Developers, privacy-focused users, custom models
✗ Not Ideal For
Non-technical users, quick results
Pricing
Free tier: Yes — open source · Last verified: July 2026
Local (free)
$0
Run on your own GPU — unlimited
POPULAR
DreamStudio
Credits
$10 = 1,000 generations approx
API
$0.002/step
Stability AI API pricing
⚠️ Prices change frequently — verify at the official site before purchasing.
Community Reviews
Real reviews from PromptAndTool members