AI Glossary · model-family

What is Stable Diffusion?

Definition

Stable Diffusion is an open-source latent diffusion model that generates images from text prompts. Released by Stability AI in 2022, it runs on consumer GPUs and powers thousands of AI art tools. On Oakgen, Stable Diffusion 3.5 is one of 30+ available image models.

Stable Diffusion pioneered accessible AI image generation. Unlike earlier models (DALL-E, Imagen) that ran only on cloud GPUs, Stable Diffusion's latent-space design lets it run on consumer hardware — a single NVIDIA RTX 3060 can generate images in seconds.

The open-source license enabled an entire ecosystem: custom checkpoints, LoRA fine-tunes, ControlNet for pose conditioning, and thousands of community tools. This made Stable Diffusion the backbone of most Automatic1111, ComfyUI, and Invoke AI workflows.

How it works

Latent-space diffusion

Stable Diffusion compresses images into a 64× smaller latent space, then trains a denoising network to reverse a gradual noising process. At inference, it starts from pure noise and progressively removes noise guided by your text prompt's embedding.

Text conditioning via CLIP

Text prompts are converted to embeddings using OpenAI's CLIP text encoder. Those embeddings condition each denoising step, steering the output toward an image that matches the prompt's semantics.

CFG scale controls prompt adherence

The classifier-free guidance (CFG) scale parameter controls how strictly the model follows your prompt. Higher values produce more literal images but can over-saturate; lower values allow the model more creative latitude.

Types & variants

SD 1.5
The original 2022 model — small, fast, most community LoRAs exist for this base.
SDXL
Higher-resolution successor (1024×1024 native) with better composition and text rendering.
SD 3 / 3.5
Current generation with improved typography, diverse subjects, and multi-subject prompts.
SD Turbo
Distilled variant that generates usable images in 1–4 steps for real-time apps.

Common use cases

Text-to-image generation for illustrations, concept art, and marketing creative
Fine-tuning on custom styles or brands via LoRAs
Image-to-image workflows (sketches → finished art, photos → illustrations)
Inpainting and outpainting for photo editing
ControlNet-guided generation with pose, depth, or edge conditioning

Try Stable Diffusion on Oakgen

Try Stable Diffusion on Oakgen →

Frequently asked questions

Is Stable Diffusion free?

The model weights are open-source and free to download. Running it yourself requires a GPU. On Oakgen, Stable Diffusion 3.5 generations cost ~10 credits each — the free tier includes 1,000 credits, enough for about 100 images.

What's the difference between Stable Diffusion and Midjourney?

Stable Diffusion is open-source and self-hostable; Midjourney is proprietary and Discord-only. SD gives you full control (LoRAs, ControlNet, custom checkpoints); Midjourney is easier for beginners but less customizable.

Can I use Stable Diffusion images commercially?

The Stable Diffusion license (CreativeML OpenRAIL-M) allows commercial use with minimal restrictions. Always check the license of specific checkpoints or LoRAs you use — some community checkpoints have additional terms.