Image Saver

ComfyUI's default Save Image node works, but it has a couple of personality quirks: filenames like ComfyUI_00042_.png, and it writes only PNG. "Image Saver" is the upgrade - date-based folders, format choice, batch-friendly names, and workflow metadata preserved in every file. If you generate a lot of images and ever find yourself renaming outputs by hand, this is the node that ends that.

What it is

NNImageSaver is an advanced output node in the bandifiu/ComfyUI-NN-custom-nodes pack. Per the README: "An advanced image saving node with support for multiple formats, automatic filename generation, batch saving, and workflow metadata preservation." It writes PNG, JPEG, or WebP to ComfyUI's output directory, and it's the pack's replacement for the stock Save Image.

How it works

Three features carry the day:

Filename templates. The filename field is a small template language with three tokens - %date (e.g. 2026_08_27), %timestamp (date + time), and %time (time only). The default is %date/%timestamp, which means a date subfolder and a time-stamped name: 2026_08_27/2026-08-27_09-41-22.png. No more 5-digit counters to decode. Slashes create folders, so %date alone gives you one folder per day.

Collision-proof names. When a file already exists, the node appends an incrementing _00001, _00002, etc. suffix instead of overwriting - the README calls this out explicitly: "Prevents filename collisions by creating unique filenames." Batch saves append _01, _02… per frame, so a 12-frame batch becomes 12 uniquely-named files.

Metadata that rides along. With save_metadata on (default), PNG output embeds the full prompt and workflow as PNG text chunks - the same data the stock node writes, so the "drag the PNG back in and get your graph" magic (covered in the KB's image-io doc) still works. WebP gets the workflow stuffed into EXIF instead (WebP has no PNG text chunks). That's the honest metadata trade-off: PNG is the round-trippable master, WebP is smaller but only carries a hint.

The inputs

• image - the tensor to save.
• filename - the template, default %date/%timestamp.
• format - png, jpeg, or webp. Default webp - worth knowing, because it surprised people when it shipped. WebP is smaller than PNG; switch to png when you want a round-trippable master.
• quality - 10–100, default 90. Applies to JPEG and WebP (PNG is lossless anyway).
• lossless - save WebP losslessly (ignored for other formats).
• save_metadata - embed prompt/workflow, default on.

Outputs: image (passthrough) and files - a list of strings with the saved relative paths, which is gold if you're automating the next step.

When to reach for it

When output organization matters to you at all. The date-folder + timestamp scheme alone is worth the swap if you generate in volume, and the files list output means you can feed the saved paths straight into a Path Info node (same pack) or a post-processing step that needs to know where the file landed. For CivitAI uploads, remember the caveat from the KB: the stock node (and this one) writes ComfyUI-format workflow chunks, not the A1111-style parameters block CivitAI's auto-linking keys on - if that matters, a dedicated CivitAI save node is still the move.

Installing

Part of bandifiu/ComfyUI-NN-custom-nodes:

cd ComfyUI/custom_nodes
git clone https://github.com/bandifiu/ComfyUI-NN-custom-nodes

Restart ComfyUI (or Manager → "NN-custom-nodes"). Deps: torch, numpy, pillow - no models. GPL-3.0, V3 backend API.

The trap to remember: default format is WebP and WebP does not round-trip a ComfyUI graph the way PNG does (the KB is blunt that PNG is the only format that rebuilds the workflow). If you're saving masters you might want to re-import, set format to png. Also note JPEG silently flattens RGBA to RGB - transparency only survives in PNG.