Save Image Webp Node

ComfyUI's built-in save node writes PNG, which is lossless and enormous. This writes WebP instead, which at high quality looks basically identical to a PNG at a fraction of the file size. If you're generating a lot of images and watching your disk fill up, that's the pitch in one sentence.

WebP is the sweet spot for most people: much smaller than PNG, sharper than JPG at the same size, and it supports both lossy and lossless modes plus embedded metadata. This node exposes all of that instead of hiding it, which is why you'd pick it over the stock saver.

The inputs that matter

The two required ones you'll actually touch are the naming controls:

• filename_prefix (default ComfyUI) - the base name for your files.
• subfolder_dir - a subfolder under the output directory, so you can keep runs organized instead of dumping everything in one place.

Then the optional knobs that make it worth having:

• quality (default 100) - WebP quality. At 100 it's visually lossless for practical purposes while still far smaller than PNG; drop it if you want even smaller files and can accept a little loss.
• lossless (default false) - flip this on for true lossless WebP when quality can't be compromised (still smaller than PNG). Note that lossless plus a high quality setting means big files - pick one philosophy.
• compression (default 4) - the encoder effort. Higher means smaller files but slower saves. It trades CPU time for bytes, not visual quality.
• optimize (default false) - extra size optimization pass.
• metadata_string and optional_additional_metadata - strings embedded into the file, handy if you want to stash prompt info or a workflow reference alongside the image.

It's an output node, so it runs whenever you queue. Its output is a STRING - the saved file's path - which you can wire into a downstream node (a logger, an uploader, a text saver) if you need to know where the image landed.

How I'd set it

For everyday work: leave quality at 100, leave lossless off. That gets you PNG-grade results at a big storage saving. Only turn lossless on for archival masters where you genuinely can't lose a bit. Bump compression if disk matters more than save speed.

Installing ComfyUI-LogicUtils

ComfyUI Manager: Install Custom Nodes → search "ComfyUI-LogicUtils" → install → restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/aria1th/ComfyUI-LogicUtils

Restart ComfyUI. WebP support rides on Pillow, which ComfyUI already has, so there's nothing extra to install for this node.

Worth knowing

The pack is aria1th's (AngelBottomless) undocumented utility collection. One practical caveat with any custom saver: because it's not the stock node, other tools that scrape ComfyUI's embedded PNG workflow metadata may not read a WebP's metadata the same way - if you rely on drag-the-image-back-in-to-recover-the-workflow, test that it survives before you commit a whole run to WebP. For pure storage-saving output, though, this is a clean upgrade over the default PNG dump.