ComfyUI Beginners Guide: Getting Started with Node-Based AI Image Generation 2025

ComfyUI is the most powerful interface for Stable Diffusion. It's also intimidating for beginners. The node-based interface looks complex, but once you understand the basics, it offers more control than any other option.

Quick Answer: ComfyUI is a node-based interface for Stable Diffusion that offers maximum flexibility and performance. Start by installing via the portable version (Windows) or git clone (Mac/Linux), download a checkpoint model, load the default workflow, and generate your first image. The learning curve is ~2-4 hours to basic proficiency.

Why ComfyUI Over Automatic1111?

Let me explain why ComfyUI is worth learning:

Advantages of ComfyUI

Performance:

• Uses less VRAM for same tasks
• Faster generation in many cases
• Better memory management
• Efficient batch processing

Flexibility:

• Complete control over every step
• Mix different models easily
• Complex workflows possible
• Easy to experiment

Reproducibility:

• Workflows are self-contained
• Share exact configurations
• Debug visually
• Understand what's happening

Advanced Features:

• Better ControlNet handling
• Complex LoRA combinations
• Multi-model pipelines
• Custom node ecosystem

When Automatic1111 Is Fine

• Quick, simple generation
• You want familiar interface
• No need for complex workflows
• Limited technical interest

My Recommendation

Learn ComfyUI. The initial learning curve pays off with more capability and better understanding of how Stable Diffusion works.

ComfyUI offers more power at the cost of initial complexity

Installation

Windows (Portable - Recommended)

Step 1: Download

1. Go to ComfyUI GitHub releases
2. Download the latest portable package
3. Extract to a folder (avoid spaces in path)

Step 2: First Run

1. Double-click run_nvidia_gpu.bat
2. Wait for initial setup (may take a few minutes first time)
3. Browser opens to http://127.0.0.1:8188

Step 3: Download a Model

1. Get a checkpoint from CivitAI or Hugging Face
2. Place in ComfyUI/models/checkpoints/
3. Refresh the interface

Mac/Linux (Git Clone)

Step 1: Prerequisites

# Python 3.10+ required
python3 --version

# Git required
git --version

Step 2: Clone and Install

git clone https://github.com/comfyanonymous/ComfyUI.git
cd ComfyUI
pip install -r requirements.txt

Step 3: Run

python main.py
# Browser opens to http://127.0.0.1:8188

Folder Structure

After installation, understand the folders:

ComfyUI/
├── models/
│   ├── checkpoints/     # Main models (.safetensors)
│   ├── loras/           # LoRA files
│   ├── vae/             # VAE files
│   ├── controlnet/      # ControlNet models
│   ├── upscale_models/  # Upscalers
│   └── embeddings/      # Textual inversions
├── input/               # Input images
├── output/              # Generated images
└── custom_nodes/        # Extensions

Understanding Nodes

ComfyUI uses nodes connected by lines. Each node does one thing. Lines carry data between nodes.

How Nodes Work

Inputs (left side):

• Receive data from other nodes
• Colored dots indicate data type
• Must connect compatible types

Outputs (right side):

• Send data to other nodes
• Color matches data type
• Can connect to multiple inputs

Node Body:

• Contains settings/parameters
• Dropdown menus for selections
• Number inputs for values

Data Types (Colors)

When connecting nodes, colors must match. You can't connect MODEL to CONDITIONING directly.

Essential Nodes

Load Checkpoint:

• Loads your model file
• Outputs: MODEL, CLIP, VAE

CLIP Text Encode:

• Converts text to conditioning
• Inputs: CLIP, text
• Outputs: CONDITIONING

KSampler:

• The actual generation happens here
• Inputs: MODEL, positive/negative conditioning, LATENT
• Outputs: LATENT (generated image)

VAE Decode:

• Converts latent to viewable image
• Inputs: VAE, LATENT
• Outputs: IMAGE

Save Image:

• Saves to output folder
• Inputs: IMAGE

Understanding node connections is key to ComfyUI

Your First Workflow

Let me walk you through creating a basic image generation workflow.

Step 1: Load the Default Workflow

When ComfyUI starts, a default workflow appears. If not:

1. Click "Load Default" button
2. Or drag in a workflow PNG

The default workflow includes everything needed for basic generation.

Step 2: Select Your Model

1. Find "Load Checkpoint" node
2. Click the dropdown
3. Select your downloaded model
4. If no models appear, you haven't placed any in models/checkpoints/

Step 3: Write Prompts

Positive prompt (what you want):

1. Find the CLIP Text Encode connected to "positive"
2. Type your prompt in the text box
3. Example: beautiful landscape, mountains, sunset, detailed, 8k

Negative prompt (what to avoid):

1. Find the CLIP Text Encode connected to "negative"
2. Type quality negatives
3. Example: blurry, low quality, bad, ugly

Step 4: Configure Settings

In the KSampler node:

seed: Random number for reproducibility. Use -1 for random.

steps: Generation steps. 20-30 for most models.

cfg: Prompt adherence. 5-8 typical.

sampler_name: Algorithm. euler or dpmpp_2m are good defaults.

scheduler: Step scheduler. normal or karras work well.

denoise: How much to change. 1.0 for text-to-image.

Step 5: Generate

1. Click "Queue Prompt" button (or press Ctrl+Enter)
2. Watch progress in the node borders
3. Image appears in Preview/Save node
4. Find saved image in output/ folder

Troubleshooting First Generation

"No checkpoint loaded":

• Ensure model is in correct folder
• Refresh page after adding models
• Check file extension is .safetensors or .ckpt

Out of memory:

• Try smaller resolution (768x768 → 512x512)
• Close other GPU-using programs
• Use a smaller model

Black or noisy image:

• Check VAE is connected
• Verify model is compatible with resolution
• Try different seed

Practical Workflows

Text to Image (Basic)

The default workflow. You have:

1. Checkpoint loading your model
2. Two CLIP encoders (positive/negative)
3. Empty Latent Image (blank canvas)
4. KSampler doing generation
5. VAE Decode revealing image
6. Save Image storing result

Image to Image

Modify an existing image:

1. Add "Load Image" node
2. Connect to "VAE Encode" node
3. VAE Encode output → KSampler latent_image input
4. Set denoise < 1.0 (0.5-0.8 typical)

Lower denoise = more of original preserved.

With LoRAs

Add style/character LoRAs:

1. Add "Load LoRA" node
2. Connect Checkpoint MODEL → LoRA MODEL input
3. Connect Checkpoint CLIP → LoRA CLIP input
4. Connect LoRA outputs → rest of workflow
5. Set strength (0.5-1.0)

Multiple LoRAs? Chain them together.

Upscaling

Improve resolution:

1. Add "Upscale Image" or model-based upscaler
2. Connect after VAE Decode
3. Save the upscaled version

Or use latent upscaling for better quality (more complex workflow).

Different workflows for different use cases

Custom Nodes

ComfyUI's power comes from custom nodes—extensions that add functionality.

Installing Custom Nodes

Method 1: ComfyUI Manager (Recommended)

1. Install ComfyUI Manager first
2. Restart ComfyUI
3. Click "Manager" button
4. Browse and install nodes
5. Restart after installing

Method 2: Manual

cd ComfyUI/custom_nodes
git clone https://github.com/[author]/[node-repo].git
# Restart ComfyUI

Essential Custom Nodes

ComfyUI Manager:

• Node/model installer
• Troubleshooting tools
• Essential for everyone

Impact Pack:

• Additional samplers
• Upscaling tools
• Face fixes

ControlNet Auxiliary Preprocessors:

• Pose detection
• Depth maps
• Edge detection

IPAdapter:

• Face/style transfer
• Character consistency
• Reference-based generation

WAS Node Suite:

• Many utility nodes
• Text tools
• Image operations

Finding Workflows

Workflows are shared as PNG files with embedded data:

• CivitAI (many workflows shared)
• OpenArt.ai (workflow library)
• Reddit r/comfyui
• GitHub repositories

Drag a workflow PNG into ComfyUI to load it.

NSFW Configuration

ComfyUI has no built-in content filters. For NSFW generation:

Use Appropriate Models

• CyberRealistic (realistic)
• Pony Diffusion (anime)
• epiCRealism (realistic)

Place in models/checkpoints/.

NSFW LoRAs

• Find on CivitAI
• Place in models/loras/
• Add Load LoRA node
• Set appropriate strength

No Additional Config Needed

Unlike Automatic1111, ComfyUI doesn't have safety checkers to disable. The models themselves determine capability.

Common Issues and Solutions

Issue: Nodes Don't Connect

Cause: Incompatible data types.

Solution: Check colors match. Can't connect MODEL directly to IMAGE.

Issue: Workflow Errors

Cause: Missing models or nodes.

Solution:

• Install missing custom nodes
• Download required models
• Check file paths

Issue: Slow Generation

Cause: High resolution, many steps, limited VRAM.

Solution:

• Lower resolution
• Fewer steps (20 is often enough)
• Close other programs
• Use fp16/fp8 if available

Issue: Same Output Every Time

Cause: Fixed seed.

Solution: Set seed to -1 for random.

Issue: Can't Find Saved Images

Cause: Looking in wrong folder.

Solution: Check ComfyUI/output/ folder.

Tips for Beginners

Start Simple

Don't try complex workflows immediately. Master the basic text-to-image first.

Save Working Workflows

When something works:

1. Click "Save" button
2. Save as .json file
3. Or save workflow image (has embedded data)

Use Preview Nodes

Add "Preview Image" nodes anywhere to see intermediate results. Helps debugging.

Learn Keyboard Shortcuts

• Ctrl+Enter: Queue prompt
• Ctrl+Shift+Enter: Queue front
• Ctrl+D: Duplicate selected nodes
• Ctrl+A: Select all
• Delete/Backspace: Delete selected

Read Node Descriptions

Hover over nodes and inputs for tooltips explaining what they do.

Join the Community

• Reddit: r/comfyui
• Discord servers
• YouTube tutorials
• CivitAI workflows

When to Use Cloud Alternatives

ComfyUI is powerful but requires:

• Hardware investment
• Learning time
• Ongoing maintenance

Platforms like Apatero offer:

• No setup required
• Character consistency built-in
• Video generation
• Pay-per-use pricing

Consider cloud if:

• You don't have capable GPU
• You want immediate results
• Character consistency is priority
• You need video generation

Consider local if:

• You have hardware
• You want maximum control
• Privacy is critical
• You enjoy technical learning

Frequently Asked Questions

Is ComfyUI harder than Automatic1111?

Initially yes. But it becomes more intuitive once you understand nodes. The visual flow helps you understand what's happening.

What GPU do I need?

8GB VRAM minimum (GTX 1070, RTX 2060 level). 12GB+ recommended for comfortable use (RTX 3060, 4070). More VRAM = higher resolution and faster generation.

Can I use Automatic1111 extensions?

No, they're incompatible. But most A1111 features have ComfyUI equivalents through custom nodes.

How do I update ComfyUI?

For portable: Download new release, copy models folder over. For git: git pull in the ComfyUI directory.

Where do I find models?

CivitAI and Hugging Face are the main sources. Download .safetensors files and place in appropriate folders.

Can ComfyUI do video?

Yes, with custom nodes for AnimateDiff, WAN, or similar. More complex than images but possible.

Getting Started Checklist

Setup:

• Download ComfyUI (portable or git)
• Install/extract to good location
• Download at least one checkpoint model
• Place model in models/checkpoints/
• Run ComfyUI successfully

First Generation:

• Load default workflow
• Select your model in Load Checkpoint
• Write simple positive prompt
• Add basic negative prompt
• Click Queue Prompt
• Find saved image in output/

Next Steps:

• Install ComfyUI Manager
• Try img2img workflow
• Add a LoRA
• Explore custom nodes
• Save your first custom workflow

Final Thoughts

ComfyUI has a learning curve, but it's the most capable Stable Diffusion interface available. The visual node system makes complex workflows possible and helps you understand how AI image generation actually works.

Start with the default workflow. Generate some images. Experiment with settings. Gradually add complexity. Within a few hours, you'll be comfortable. Within a few days, you'll prefer it to other interfaces.

The time investment pays off in capability and understanding. And the workflows you create can be saved, shared, and refined over time.

Related guides: Stable Diffusion NSFW Settings, Character Consistency Guide, Best Uncensored AI Generators