by. Haoming
2025 Feb.

_{corresponding Webui version: v1.10.1}
^{corresponding Forge version: v2.0.1}

Introduction

Stable Diffusion is a text-to-image generative AI model, similar to online services like Midjourney and Bing. Users can input prompts (text descriptions), and the model will generate images based on these prompts. The main advantage of Stable Diffusion is that it is open-source, completely free to use, and can be run locally without any censorship.

Furthermore, there are many community-developed extensions (tools) that can perform a wide range of functions, as well as numerous community-trained models that can achieve various styles and concepts, giving users full creative control over the generations.

Index

1. Getting Started
   • Hardware Requirement
   • Popular UIs
2. Models
   • Architecture
   • Checkpoint
   • UNet
   • Text Encoder
   • VAE
   • Embedding
   • LoRA
   • How to Use
   • Download
   • Diffusers
3. Terminologies
   • Tabs
   • Parameters
4. Settings
   • Saving images/grids
   • Optimizations
   • Stable Diffusion
   • Live Previews
   • System
5. Tips & Tricks
   • X/Y/Z Plot
6. Extensions
   • Installation
   • Update
   • Recommendations
   • ControlNet
7. LoRA Training
8. Learning Resources

Getting Started

This section will cover some basic information on how to start generating images locally

Hardware Requirement

To run AI models locally, a Graphics Card (GPU) from Nvidia is required

Note

While it is possible to run Stable Diffusion on AMD, Apple, or even Intel GPUs, the setup can be more complicated and the processing speed is usually slower

When choosing a GPU, VRAM is the most important spec. Sufficient VRAM is essential to fit the entire model into memory; processing speed is only relevant once the model can be fully loaded. If your GPU does not have enough VRAM, the model will be partially loaded into system swap memory instead, significantly reducing the processing speed by up to ten times. Additionally, aim for the RTX 30 series or later, as older GPUs have limited support for half precision.

These are the reasons why, RTX 3060 (12 GB VRAM) is generally recommended over RTX 3070 (8 GB VRAM) and RTX 2080 (11 GB VRAM).

List of Recommendation

• Budget: RTX 3060 (12 GB VRAM)
• Entry Level: RTX 4060 Ti (16 GB VRAM)
• Enthusiast: Second-Hand RTX 3090 (24 GB VRAM)
• Professional: RTX 4090 (24 GB VRAM)
• Baller: RTX 5090 (32 GB VRAM)

What I am using: RTX 4070 Ti Super (16 GB VRAM)

Tip

If you do not have a capable system, there are also (paid) online services for Stable Diffusion

Popular UIs

Listed below are some popular User Interfaces to run Stable Diffusion:

• Automatic1111 Webui: The classic frontend that helped popularizing Stable Diffusion in the early days, with a large community and extension supports; though development seems to be halted as of now

• Forge Webui: A frontend based on Automatic1111, with a more optimized memory management that allows even low-end devices to run Stable Diffusion; though some may find Gradio 4 unresponsive; and development seems to be halted as of now

Tip

Installation Guide for Automatic1111 / Forge

• ComfyUI: An advanced node-based frontend, providing the maximum flexibility for users to build custom complex workflows; though the learning curve is steeper as a result

• Fooocus: A rather simple frontend, suitable for those who simply want beautiful artworks by just writing a prompt

• SwarmUI, InvokeAI, SD.Next: Other notable frontend; though personally I've never tried them

• Stability Matrix: A platform that simplifies the frontend installation and model management

What I am using: Forge Classic, based on the "previous" (Gradio 3) version of Forge, with a few minor updates and optimization added

Models

This section will cover various things the word "model" can refer to in the context of Stable Diffusion

Architecture

There has been numerous architectures released over the years. Listed below are the most widely adopted versions as of now:

• Stable Diffusion 1.5: The good ol' version that basically brought local image generation into the mainstream. As the smallest model with a base resolution of only 512x512 and an inability to generate hands reliably, its quality is less comparable nowadays. But it remains quite popular thanks to its lower system requirements.
  • (hereinafter referred to as SD1 below)
• Stable Diffusion XL: The newer and bigger version with a base resolution of 1024x1024. It now understands prompts better and has a lower chance of generating eldritch abominations. But it also has considerably higher system requirements.
  • (hereinafter referred to as SDXL below)
• Pony Diffusion V6 XL: A specialized version of SDXL that underwent extensive training, causing many features to be incompatible between the two, resulting in a distinct category of its own. This model was specially fine-tuned on "Booru tags" to generate anime/cartoon images, with good prompt comprehension and the ability to generate correct hands/feet.
  • (hereinafter referred to as Pony below)
• Illustrious: Another specialized version of SDXL that was fine-tuned on "Booru tags" to generate anime images. It has even better prompt comprehension without a broken Text Encoder. Additionally, since the training dataset was not obfuscated, many popular characters can be directly prompted.
  • TL;DR: Illustrious series is significantly better than Pony series nowadays

Tip

Booru Tags refers to the comma-separated tags used by anime image boards; see this post of Hatsune Miku for example

• Flux: One of the latest architectures, capable of generating legible text and next-gen quality, with next-gen hardware requirements...

  • (Don't even bother if you have less than 12 GB VRAM)
  • There are 3 variants:
    • pro: Only available through paid online services
    • dev: Distilled from pro, uses standard number of steps (non-commercial)
    • schnell: Further distilled from dev, requires fewer number of steps
  • Technically, this is not Stable Diffusion

• Stable Diffusion 3.5: Another one of the latest architectures

  • There are 2 variants:
    • large: Quality is comparable to Flux; can also generate texts
    • medium: Slightly worse quality; but is also lighter to run
  • (Though, seems that there is no wide adoption yet)
  • (hereinafter referred to as SD3 below)

Important

Models of different architectures are not compatible with each other (eg. a LoRA trained for SD1 will not work with SDXL, etc.)

What I am using: Hassaku XL (Illustrious) - A model further trained on Illustrious

Checkpoint

Checkpoint is what "model" usually refers to. It is the whole package that contains the UNet, Text Encoder, and VAE mentioned below.

• For SD1 and SDXL, models are usually distributed in a single checkpoint
• For Flux and SD3, the components are usually distributed separately due to the large size

Note

Put Checkpoint in ~webui\models\Stable-diffusion

UNet

U-Net is the core component that processes the latent noises to generate the image.

Note

Put UNet in ~webui\models\Stable-diffusion

Note

For Flux and SD3, the "core component" is DiT instead of U-Net, but people generally still call them UNet on the internet

Text Encoder

Text Encoder is the component that converts the human-readable prompts into vectors that the model understands.

• SD1, SDXL, SD3, and Flux all use the small Clip text encoder(s) (~300 MB)
• SD3 and Flux additionally use the big T5 text encoder (~10 GB at fp16 precision)

Note

Put Text Encoder in ~webui\models\text_encoder

VAE

VAE is the component that converts RGB images to / from latent space

Note

Put VAE in ~webui\models\VAE

Embedding

Embedding (or Textual Inversion) is a technique used to train the Text Encoder to learn specific concepts (eg. Characters, Style, etc.)

Note

Put Embedding in ~webui\embeddings

LoRA

LoRA (and LyCORIS) is a technique used to train the UNet (and optionally Text Encoder) to learn specific concepts (eg. Characters, Style, etc.)

Important

Most LoRA requires trigger words to function correctly, make sure to read the description

Note

Put LoRA in ~webui\models\Lora

How to Use

• To change Checkpoint, select from the Stable Diffusion checkpoint dropdown at the top of the UI
  • To use the separated components in Forge, refer to this Announcement
• To use Embedding, click on the model card to add the filename to the prompt field
• To use LoRA, click on the model card to add the syntax to the prompt field
• To manually set a VAE, select from the SD VAE dropdown in the VAE section of the Settings tab

Tip

• If you don't see your newly added models, remember to click the Refresh button first
• By default, the Webui should detect the architecture of LoRAs and hide incompatible ones automatically; if you encounter a situation where known-compatible LoRAs are not showing up, you can enable the Always show all networks on the Lora page toggle in the Extra Networks section of the Settings tab

Download

CivitAI is a site that hosts all sorts of models and user-generated resources like guides. When browsing, you can click the Filters to look for a specific model type or architecture. Every page contains user comments, ratings, and samples. Remember to check the Base Model in the Details before downloading.

Note

.safetensors is a format to store the weights safely; always choose .safetensors if available

Diffusers

On HuggingFace, you may come across repositories where each component is separated into sub-folders, such as epiCRealism. This format is used by the Diffusers library. However, the Webui does not support this format. Usually you can find a link to the checkpoint format used by the Webui instead in the Model card.

Terminologies

This section will cover some noun. used within the Webui

Tabs

• txt2img: Generate an image based on prompts
• img2img: Generate an image based on another image and prompts
• Extras: Postprocess images (incl. Upscale, Caption, Crop, etc.)
  • You can download upscaler models from OpenModelDB

Note

Put upscaler in ~webui\models\ESRGAN

What I am using: 2x-NomosUni-esrgan-multijpg

• PNG Info: You can upload a generated image to see the infotext (ie. the prompts and parameters used), provided that the metadata was not removed from the image
• Checkpoint Merger: The easiest way to spam more junks onto CivitAI
• Train: Broken; use Kohya_SS instead
• Settings: Settings 💀
• Extensions: Install & Manage Extensions

Parameters

• Prompt: The text for what you want in the output
• Negative Prompt: The text for what you don’t want in the output
• Sampling Method: Read this article for explanations and examples
  • TL;DR: Euler a tends to generate smoother images, suitable for anime models; DPM++ 2M Karras tends to generate detailed images, suitable for realistic models

Note

Since Webui v1.9.0, the Sampler and Scheduler are now two separated dropdowns

• Sampling Steps: The number of denoising iterations
  • 20 ~ 32 is generally enough
  • Low value causes the output to be noisy; High value takes longer with no benefit
  • LCM and Lightning models can generate decent images with as few as 4 steps
  • Turbo models can even generate images with just 1 step
• Hires. Fix: Upscale then run through the pipeline a second time to improve output
• Refiner: Obsolete; just ignore it...
• Width/Height: The resolution of the generated image

Important

Keep it at 512x512 for SD1 models; around 1024x1024 for SDXL, SD3, Flux models; and keep both width and height at multiples of 64 (eg. 1152x896)

• Batch Count: How many batches to generate (in series)
• Batch Size: How many images per batch (in parallel)
• CFG Scale: How strong the prompts influence the output
  • 4 ~ 8 is generally fine
  • Low value generates blurry images; High value generates "burnt" (really high-contrast and distorted) images
  • Generally, the lower the steps, the lower the CFG
    • eg. for LCM, Lightning, Turbo, set it to 1 instead
  • For Flux models, CFG should be set to 1 as well
• Seed: The random seed that affects the latent noise generation
  • You should get the same output if you use the same parameters and seed

Tip

Go to the Stable Diffusion section of the Settings tab, and change Random number generator source to CPU for the maximum repeatability across different systems

Settings

This section will cover some settings recommended to change or frequently asked about

Saving images/grids

These settings modify the saving behavior

• File format for images:
  • png is lossless with the largest filesize
  • jpg is lossy with the smallest filesize
  • webp is in-between, but takes slightly longer to save
• Save copy of large images as JPG:
  • If enabled, when you generate a high-resolution image, it would additionally save a .jpg once the filesize threshold is reached

Optimizations

These settings can improve the generation speed

• Cross attention optimization:
  • xformers if enabled; sdp - scaled dot product otherwise
  • Automatic for Forge
• Pad prompt/negative prompt - Enable
• Persistent cond cache - Enable
• Batch cond/uncond - Enable

Stable Diffusion

These settings affect the generation details

• Enable quantization in K samplers:
  • I myself did enable this, though the effect seem minimal
  • Seems to be always enabled for Forge
• Emphasis mode:
  • Setting it to No norm prevents a problem where certain SDXL models tend to generate pure noises
• Clip skip:
  • Long story short, some models work better with 2; but setting it to 2 does not worsen the results for other models anyway. So just set it to 2...

Live previews

These settings affect the preview during generation

• Live preview method:
  • TAESD, significantly faster
• Return image with chosen live preview method on interrupt:
  • Enable, makes interrupts faster

System

These settings modify the behavior of the Webui

• Automatically open webui in browser on startup:
  • Change this if you don't want the browser to start automatically
• Show gradio deprecation warnings in console:
  • Disable, like why...

Tips & Tricks

• General Knowledge and Webui Features
• Tutorial for X/Y/Z Plot

Extensions

Extensions are basically 3rd-party add-ons that provide additional features not native to the Webui

How to Install

1. Go to the Extensions tab
2. Switch to the Install from URL sub-tab
3. In the URL for extension's git repository field, paste in the link to the Extension's GitHub page
   • eg. https://github.com/Haoming02/sd-webui-tabs-extension
4. (Optional) In certain use cases, you may need to fill out the Specific branch name field, usually for development or compatibility reasons
5. (Optional) You can fill out Local directory name to set a custom folder name (The practical use of this is to sort Extensions)
6. Click the Install button
7. Some Extensions may install additional dependencies; this can take some time
8. Once the installation is finished, an Installed into ... line will appear under the Install button
9. Switch to the Installed sub-tab
10. Click the Apply and restart UI button

How to Update

1. Go to the Extensions tab
2. Click the Check for updates button
3. Once finished, some Extensions may show the behind HEAD label in the Update column
4. Click the Apply and restart UI button
5. Some Extensions may install additional dependencies; this can take some time

Tip

Sometimes, after clicking the Apply and restart UI button, the browser will refresh first before the Webui is actually ready, and you may see a bunch of disconnected errors or broken UI texts. When this happens, do not use the Webui yet. Wait for the console to show the Running on local URL: ... line, then manually refresh (F5) the browser again. After which, the Webui will be good to go again.

Recommendations

Some essential Extensions that basically everyone should have

• ControlNet
  • Tutorial for ControlNet - The biggest strength Stable Diffusion has over proprietary services
• RegionalPrompter / ForgeCouple
  • How to Generate Multiple Characters within the same Image
• MultiDiffusion & TiledVAE
  • How to Generate Extremely High Resolution Image without OOM

Shameless Self Promotions

Some Extensions written by yours truly

• Prompt Format
  • Format your prompts by removing extra spaces and commas
• Tabs Extension
  • Convert Extensions into tabs for better organization
• Easy Tag Insert
  • Trivialize inserting prompts by making shortcut buttons
• Image Comparison
  • Easily compare images within the Webui
• IC Light
  • Manipulate the illumination of images
• Yapping
  • Save parameters as preset buttons
• Boomer
  • Revert some UI changes for improved usability

LoRA Training

• How to Train LoRA

Resources

Some more places to learn about Stable Diffusion

• Reddit r/StableDiffusion
• Webui Features
• Youtube Sebastian Kamph
• Youtube OlivioSarikas
• Forge Troubleshoot
  • eg. Press anykey to continue...

Support Me

• If you appreciate my works and wish to support me, you can buy me a coffee~

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