Stable Diffusion

Stable Diffusion is a family of open-weight latent diffusion models developed by Stability AI that generate images from text prompts. Unlike Midjourney and OpenAI’s GPT Image models (which replaced DALL-E, retired on 12 May 2026), the model weights are publicly available. You can run them locally on consumer hardware (an NVIDIA GPU with 6 GB VRAM or an Apple Silicon Mac), fine-tune them on custom image datasets with LoRA or DreamBooth, and integrate them into production systems via the Stability AI API or through open-source inference servers. The current generation is still Stable Diffusion 3.5 (2024), which improves typography and prompt adherence over earlier versions; as of September 2026 Stability AI has not released a successor image model, and its recent open releases have been hardware-optimised SD 3.5 variants and audio models.

Installation: Diffusers library

The Hugging Face diffusers library is the reference implementation. It runs on NVIDIA GPUs, Apple Silicon, and CPU (slow).

pip install diffusers transformers accelerate torch

import torch
from diffusers import StableDiffusion3Pipeline

pipe = StableDiffusion3Pipeline.from_pretrained(
    "stabilityai/stable-diffusion-3.5-medium",
    torch_dtype=torch.bfloat16
)
pipe = pipe.to("cuda")  # or "mps" for Apple Silicon

image = pipe(
    prompt="A dark industrial server room, red neon lights, deep shadows, editorial photography",
    negative_prompt="blurry, low quality, text, watermark",
    num_inference_steps=28,
    guidance_scale=4.5,
    height=1024,
    width=1024,
).images[0]

image.save("output.png")

Stability AI API

For production use without local GPU infrastructure, the Stability AI REST API provides SD 3.5 access at per-image pricing.

pip install requests

import requests
import base64

response = requests.post(
    "https://api.stability.ai/v2beta/stable-image/generate/sd3",
    headers={
        "Authorization": "Bearer YOUR_STABILITY_API_KEY",
        "Accept": "image/*"
    },
    files={"none": ""},
    data={
        "prompt": "Austrian alpine landscape at dawn, golden hour, photorealistic, 4K",
        "negative_prompt": "blurry, oversaturated, text",
        "model": "sd3.5-medium",
        "aspect_ratio": "16:9",
        "output_format": "webp",
    }
)

with open("landscape.webp", "wb") as f:
    f.write(response.content)

LoRA fine-tuning for brand images

LoRA (Low-Rank Adaptation) adds a lightweight adapter on top of the base model trained on your specific images. The result is a model that generates images in your brand style without retraining the full model.

A LoRA training run for a product brand takes 20-30 images and 30-90 minutes on a single A100.

from diffusers import StableDiffusion3Pipeline
from peft import PeftModel
import torch

base_model = StableDiffusion3Pipeline.from_pretrained(
    "stabilityai/stable-diffusion-3.5-medium",
    torch_dtype=torch.bfloat16
)

# Load LoRA weights trained on your brand images
base_model.load_lora_weights("./your-brand-lora")
base_model = base_model.to("cuda")

image = base_model(
    prompt="product photo of a coffee mug, brand style, studio lighting",
    num_inference_steps=28,
    guidance_scale=4.5,
).images[0]

image.save("brand-output.png")

Pricing (Stability AI API)

Stability bills in credits: 1 credit = $0.01 (platform.stability.ai/pricing , checked 26 September 2026).

Local inference is free after the one-time cost of a GPU. An NVIDIA RTX 3080 (€500-700 used) generates 1,000+ images per day.

Comparison with alternatives

DALL-E 2 and DALL-E 3 were retired from the OpenAI API on 12 May 2026; see the Midjourney vs DALL-E vs Stable Diffusion comparison for the current OpenAI and Midjourney lineups.

ControlNet: spatial control over generation

ControlNet takes a reference image (pose skeleton, depth map, edge map, or semantic map) and uses it to constrain the layout of the generated image. This is essential for product photography consistency, character pose control, and architecture visualization.

from diffusers import StableDiffusionControlNetPipeline, ControlNetModel
import torch

controlnet = ControlNetModel.from_pretrained(
    "lllyasviel/sd-controlnet-canny",
    torch_dtype=torch.float16
)

pipe = StableDiffusionControlNetPipeline.from_pretrained(
    "stable-diffusion-v1-5/stable-diffusion-v1-5",  # formerly runwayml/stable-diffusion-v1-5
    controlnet=controlnet,
    torch_dtype=torch.float16,
).to("cuda")

# edge_image: preprocessed edge map from your reference image
image = pipe(
    prompt="product photo, marble countertop, studio lighting, white background",
    image=edge_image,
    num_inference_steps=20,
).images[0]

When not to use Stable Diffusion

Photorealistic faces with identity preservation: Without fine-tuning on a specific person’s face, SD 3.5 is inconsistent across generations. For consistent character identity, tools like IP-Adapter or a person-specific LoRA add significant setup overhead.

Copyrighted style replication: Training a LoRA on copyrighted artwork to reproduce that style is a live legal question across multiple jurisdictions. The EU AI Act and emerging case law may make this an explicit risk by 2027.

Real-time generation at high resolution: SD 3.5 Medium generates a 1024x1024 image in 8-12 seconds on an A100. For sub-second generation at scale, Flux.1 Schnell or purpose-built inference APIs (Fireworks, together.ai) are faster.

Non-technical users who need a GUI: If the team does not write Python, ComfyUI or Automatic1111 provide browser-based GUIs with no code, but still require local GPU installation. Midjourney or Adobe Firefly are the simpler choice for non-technical users.

Further reading

• Stability AI API documentation : REST endpoints, model IDs, pricing
• Hugging Face Diffusers library : Python API reference, tutorials, LoRA training guides
• ComfyUI : Node-based visual workflow builder for SD, recommended for non-Python users
• Civitai : Community library of thousands of free LoRA and checkpoint models
• SDXL LoRA training guide on Hugging Face : Detailed fine-tuning tutorial for SDXL
• LLM Landscape 2026 : How image generation models fit into the broader AI landscape
• What is a Machine Learning Model? : Foundational concept behind diffusion models

Sources

1. Stability AI models on Hugging Face (no image model newer than SD 3.5; checked 25 September 2026): https://huggingface.co/stabilityai
2. OpenAI, Deprecations (DALL-E 2 and DALL-E 3 retired 12 May 2026): https://developers.openai.com/api/docs/deprecations
3. Black Forest Labs, FLUX.2 [dev] model card (FLUX non-commercial licence, November 2025): https://huggingface.co/black-forest-labs/FLUX.2-dev
4. Black Forest Labs, FLUX.2 [klein] 4B model card (Apache 2.0, January 2026): https://huggingface.co/black-forest-labs/FLUX.2-klein-4B
5. Midjourney, “V8.1 is now the default model” (11 June 2026): https://updates.midjourney.com/v8-1-is-now-the-default-model/
6. Stable Diffusion v1.5 repository (moved from runwayml): https://huggingface.co/stable-diffusion-v1-5/stable-diffusion-v1-5