Seed-Nodes: ImagePixelator

Pixelation is one of those effects that's trivial to describe and mildly annoying to wire up by hand in ComfyUI - you'd normally need a resize-down, resize-back dance plus the right interpolation mode. ImagePixelator does the whole thing with one input. It's from the ComfyUI-Seed-Nodes pack, it does exactly one thing, and there's something refreshing about that.

How it works

The mechanism is classic and simple: the image is downscaled to width / pixel_block by height / pixel_block, then scaled back up to its original size - both times using nearest-neighbor interpolation. Nearest-neighbor is the whole trick: it doesn't blend, it just picks a single color per block, so you get crisp chunky mosaic blocks instead of a soft blur. Each block of pixel_block × pixel_block source pixels collapses into one solid square.

It keeps RGBA input as RGBA output, so transparent images stay transparent through the effect - handy if you're pixelating cutouts or sprites rather than full photos.

The inputs that matter

Just one real dial:

• pixel_block - the block size in pixels (1–100, default 10). 10 turns every 10×10 area into one block, which reads as "retro game." 30+ gets into "censor bar for a news report" territory. Below ~4 you're barely doing anything.

Plus the image input, of course. Output is a single image tensor at the same resolution as the input.

What it's actually good for

Three honest use cases. Privacy and content sanitization - drop it on a face or a region before sharing a render; it's the blunt instrument that actually defeats recognition, unlike a Gaussian blur that people can argue about. Aesthetic - 8-bit / pixel-art look for thumbnails or stylized stills. And batch work: because it's cheap and resolution-independent, you can pixelate a whole folder of images without thinking about it (pair it with LoadMultipleImages from the same pack and you're done). It's also a legit debugging tool - pixelating down hides a lot of VAE noise and lets you eyeball composition without squinting.

How to install it

Pack install, as with everything in ComfyUI-Seed-Nodes:

cd ComfyUI/custom_nodes
git clone https://github.com/Aerse/ComfyUI-Seed-Nodes
# restart ComfyUI

Or ComfyUI Manager → search "ComfyUI-Seed-Nodes". No model downloads, pure Pillow + numpy, runs fine on CPU.

Common issues

• Not pixelated enough / too much - that's the pixel_block dial; this node has no other knobs, so there's nowhere else to be confused.
• Edges look wrong - if your result looks soft instead of blocky, check that whatever you're viewing it through isn't resampling. The node itself always uses nearest-neighbor.
• Nothing appears in the node list - the pack needs a ComfyUI restart after install.

Simple tool, honest behavior. You won't use it every day, but when you need a mosaic, it's the fastest one-input fix in the graph.