PreviewImageWEBP

The stock PreviewImage node writes lossless PNG every single time, which is fine for one image and mildly annoying once you're blasting through dozens of variations in a row - each preview write is bigger and slower than it needs to be, and it adds up when you're just eyeballing results before committing to a real save. This node swaps the preview format to WEBP, which is dramatically smaller at visually-indistinguishable quality.

How it works

It's a drop-in replacement for the standard preview slot: same images input, no outputs (it's a terminal node in the graph, exactly like PreviewImage or SaveImage). The difference is entirely in the encode step.

• quality (0–100, default 83) - WEBP's quality dial. 83 is a solid default: noticeably smaller files than PNG with no visible loss for review purposes. Note that even at 100 this is WEBP's lossy mode topping out near-lossless, not literally pixel-identical to the source - if you need a bit-exact archive copy, that's what your actual save node is for, not this preview.
• method - one of default, fastest, slowest. This is WEBP's encoder effort setting: fastest trades some compression efficiency for speed (good when you're churning through a big batch and just want to glance at results), slowest squeezes files smaller at the cost of encode time.

Why you'd reach for it

Anywhere you're generating a lot of throwaway previews - big batches, XY-style comparison grids, quick iteration loops where you're rejecting nine out of ten results - the disk and UI-load savings from smaller preview files are real. It's not meant to replace your actual output save step; it's meant to make the "look and decide" part of the loop lighter.

How to install it

Through ComfyUI Manager: search "SP-Nodes," install, restart. Or clone it manually:

cd ComfyUI/custom_nodes
git clone https://github.com/bananasss00/ComfyUI-SP-Nodes

Restart ComfyUI and it'll show up alongside the stock image nodes under the image category.

Common issues

This is a genuinely low-friction node - there isn't much to trip over. The one thing worth knowing going in: it's a preview, not a save. If you want to keep the actual pixels of something you liked, use SaveImage (or an equivalent save node) downstream; don't rely on the preview cache as your archive. Beyond that, if file sizes aren't shrinking the way you expect, check quality and method aren't both cranked toward maximum fidelity - that's the WEBP equivalent of asking for lossless and then being surprised it isn't small.