SaveAnimatedPNG_motorway_edition

You've got a batch of frames on the Motorway bus and you want them as an animation. SaveAnimatedPNG_motorway_edition is the clone of ComfyUI's built-in SaveAnimatedPNG that does exactly that - it takes an image batch and writes one animated PNG (APNG) file. The pitch for APNG is that it plays everywhere a browser plays PNGs, which means no ffmpeg, no codec drama, just double-click and it animates. The cost is file size: PNG compression doesn't do temporal compression, so a 24-frame animation is basically 24 full images stuffed in a row. For short loops and preview animations it's fine; for anything longer you want WEBM.

Because it's a save node, there's no output wire that matters - but that's where the motorway-edition quirk shows up. Every *_motorway_edition node is a generated clone that always returns the Motorway bus, and this one is not flagged as an output node, so ComfyUI's UI won't treat it as a workflow endpoint the way it does the stock SaveAnimatedPNG. The file still gets written to ComfyUI/output/ - it just won't show up as the "final output" highlight, and the author's README explicitly warns that output nodes are among the ones that "won't work" in this family. Plan for the file to land in your output folder and check there.

The widgets you set:

• filename_prefix (default ComfyUI) - the file name (ComfyUI appends the counter and timestamp). You can use formatting like %date:yyyy-MM-dd% to date-stamp it.
• fps (default 6) - animation speed. 6 is the classic low-fps preview rate; nudge it up for actual motion.
• compress_level (default 4, 0–9) - PNG compression. Higher = smaller file, slower to write. 4 is a good middle; 9 if size matters more than write speed.

The images themselves are pulled from the bus by key - that's what INPUT_images_key (default images) is for. Whatever key you've been storing your image batch under on the bus, type it there. The motorway convention applies to the source: if some earlier node wrote its output under a different key name, that's the string you put in.

Installing it

Part of ComfyUI_agilly1989_motorway. ComfyUI Manager: search ComfyUI_agilly1989_motorway, install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/agilly1989/ComfyUI_agilly1989_motorway

No extra Python dependencies, no model files. APNG needs nothing beyond what ComfyUI already ships.

The catch

The pack-wide gotchas apply double here. Release 1.1.7 has the clone nodes disabled - uncomment the two ClonedNodeMapping lines in custom_nodes/ComfyUI_agilly1989_motorway/__init__.py and restart, or this node won't exist. And per the README, save/output nodes are exactly the kind this experimental project ("BIG BROKEN WITH ASYNC WILL FIX WHEN I GET THE TIME/MOTIVATION" is the literal first line) admits it doesn't fully support. If you're converting an existing workflow to the Motorway just to save files, the stock SaveAnimatedPNG is the safer bet - this one is for keeping the whole pipeline, save included, on the bus.