ComfyUI: Upscaling with Neural Network models

ComfyUI Try it →Watch full video →pixaroma · Feb 2026

Demo summary

This clip shows how to use the 'Upscale Image (using Model)' node in ComfyUI with various PTH models like UltraSharp and 8x upscalers to sharpen and reconstruct details.

Step-by-step

Add the 'Upscale Image (using Model)' node to your workflow
Add the 'Upscale Model Loader' node and connect it to the upscale node
Open the ComfyUI Manager and select 'Model Manager'
Filter by type 'upscale' to find and install PTH models like UltraSharp
Click 'Refresh' on the main UI to load newly installed models
Select your desired model in the 'Upscale Model Loader' node
Adjust the 'scale_by' value in the upscale node to multiply or reduce the model's native output size

Options

Manually download PTH models and place them in the 'upscale_models' folder
Use 2x, 4x, or 8x models depending on target resolution
Reduce the final output size of a high-multiplier model by setting 'scale_by' to a decimal (e.g., 0.5)

Watch out for

These models are trained neural networks, not diffusion models, and do not use prompts or noise to generate images
The final image size is a product of the model's native multiplier and the 'scale_by' value

Tips

Experiment with different models as some are optimized for photos while others are better for illustrations
If an image appears too sharp, try a different model or adjust the scaling factors
Use the Model Manager to easily track which models are already installed in your directory

Highlights

“It's very easy to install... The upscale is quite quick. It can take about 5 to 10 seconds”

All demos from “How to Upscale Images in ComfyUI (Ep05)”

1:491:28Simple non-AI image resizing in ComfyUIThe creator demonstrates a basic 'Upscale Image By' node that performs a standard resolution increase without AI, similar to Photoshop resizing, and uses an RG3 image comparer node to view the results.ComfyUI· AI Image Upscaler
3:193:04Upscaling with Neural Network modelsCurrentThis clip shows how to use the 'Upscale Image (using Model)' node in ComfyUI with various PTH models like UltraSharp and 8x upscalers to sharpen and reconstruct details.ComfyUI· AI Image Upscaler
6:233:22Tiled Diffusion upscaling with Zimage TurboThe creator walks through a complex workflow using Tiled Diffusion and the Zimage Turbo model to upscale images while managing VRAM by processing the image in smaller tiles.ComfyUI· AI Image Upscaler
9:451:24Upscaling with Nunchaku Flux ManiaA demonstration of using a modified Flux.1 Dev model (Flux Mania) via Nunchaku nodes to perform a 2x upscale that enhances skin textures and fine details.ComfyUI· AI Image Upscaler
11:103:10High-fidelity upscaling with SeedVR2The video shows the setup and execution of the SeedVR2 node pack, demonstrating how to select specific models and adjust resolution for sharp, consistent upscaling results.ComfyUI· AI Image Upscaler
14:271:304K upscaling with Nano Banana Pro APIThe creator demonstrates using the paid Nano Banana Pro node to achieve 4K resolution upscaling through an external API, showing the significant detail improvement in the final result.ComfyUI· AI Image Upscaler
15:570:46Creative upscaling with Recraft modelThis clip shows the Recraft node in action, which performs a 'creative upscale' to generate clean, realistic variations of an image with added textures.ComfyUI· AI Image Upscaler
Watch “How to Upscale Images in ComfyUI (Ep05)” →

AI Image Upscaler

30:073:41Upscaling images using modelsDemonstrates upscaling a low-resolution 512x512 image using the 4X Ultra Sharp model to add clarity and detail.AI Search
36:021:32Using Preview Chooser for selective upscalingShows how to use the Image Chooser node to generate a batch of images and selectively progress only one specific image to the upscaler.AI Search
43:496:52Tiled upscaling with Ultimate SD UpscaleA detailed demo of the Ultimate SD Upscale node, showing how tiled upscaling generates significantly higher facial detail than standard upscaling.AI Search
2:432:38Generate and upscale images with Flux KontextThe creator demonstrates setting up a basic Flux Kontext workflow in ComfyUI, generating a character image, and then using a KSampler-based upscaler to increase resolution.pixaroma
9:521:53Upscale an existing image to 4K with PiDThe video demonstrates uploading a landscape photo into a ComfyUI workflow and using the PiD (Pixel Diffusion) model to upscale it to 4096 resolution in under 10 seconds.AI Search
13:200:38Compare original vs upscaled image using RG3 nodesThe user adds an 'image compare' node by RG3 to the ComfyUI canvas to show a side-by-side slider comparison of the blurry original image versus the sharp PiD upscaled result.AI Search
14:274:08Generate and upscale images using Zee Image and PiDA demonstration of a combined workflow where Zee Image Turbo generates a 1K image of a red panda which is then automatically passed into the PiD upscaler for a 4K final output.AI Search
1:491:28Simple non-AI image resizing in ComfyUIThe creator demonstrates a basic 'Upscale Image By' node that performs a standard resolution increase without AI, similar to Photoshop resizing, and uses an RG3 image comparer node to view the results.pixaroma
3:193:04Upscaling with Neural Network modelsCurrentThis clip shows how to use the 'Upscale Image (using Model)' node in ComfyUI with various PTH models like UltraSharp and 8x upscalers to sharpen and reconstruct details.pixaroma
6:233:22Tiled Diffusion upscaling with Zimage TurboThe creator walks through a complex workflow using Tiled Diffusion and the Zimage Turbo model to upscale images while managing VRAM by processing the image in smaller tiles.pixaroma
9:451:24Upscaling with Nunchaku Flux ManiaA demonstration of using a modified Flux.1 Dev model (Flux Mania) via Nunchaku nodes to perform a 2x upscale that enhances skin textures and fine details.pixaroma
11:103:10High-fidelity upscaling with SeedVR2The video shows the setup and execution of the SeedVR2 node pack, demonstrating how to select specific models and adjust resolution for sharp, consistent upscaling results.pixaroma