Save Image (BMP)

Save Image (BMP) writes .bmp files. That's the entire job, and honestly it's a niche one. BMP is a 1980s-era, uncompressed (or lightly RLE-compressed) bitmap format that's huge by modern standards - a 1024×1024 BMP is a few megabytes where the same image as JPG is a hundred kilobytes. So who needs this? People targeting software that only reads BMP: legacy applications, some print-to-archive pipelines, firmware UI tooling, certain industrial/embedded workflows, and the occasional game modding pipeline. If none of that describes you, you can read this article for the knowledge and move on - the pack's other savers will serve you better.

Mechanically it's the simplest node in the pack. One image input, one filename prefix, no outputs, no quality knob - BMP doesn't really have "quality," it has pixel data. Frames are flattened to RGB (so alpha is dropped), written with a fixed 72 DPI tag, and each frame in the batch becomes its own numbered .bmp file in ComfyUI/output.

The one input you'll touch

• Images (IMAGE) - the batch to save.
• Filename Prefix - supports the pack's token system: %date:yyyy-MM-dd%, %year%, %month%, %hour%, %minute%, %second%, %width%, %height%. Right-click the node for "Insert Filename Token."

That's it. Two inputs, terminal node, done.

The honest verdict

The practical question isn't "how do I use this," it's "do I actually need BMP at all." For almost every real-world export, PNG (lossless, alpha, compression, metadata) or JPG (tiny, universal) beats it, and the advanced BMP node in this pack at least adds 32-bit alpha and DPI control if you're truly stuck on the format. The niche where plain BMP wins is maximum compatibility with software that hasn't been updated since the format's heyday - and in that world, a 24-bit RGB BMP is the safest possible handoff. If you're doing that, this node saves you the trip to an image editor. If you're not, you've now learned why BMP files are so big, which is its own kind of value.

One thing to note: because frames are converted to RGB, any transparency is flattened (typically against black). If your workflow needs a BMP with alpha, that's the advanced variant's job (32-bit mode), not this one's.

Install

Part of ComfyUI-Image-Process:

cd ComfyUI/custom_nodes
git clone https://github.com/wakaura-asaho/comfyui-image-process
pip install -r comfyui-image-process/requirements.txt

then restart - or find the pack in ComfyUI Manager. Dependencies are numpy, Pillow 12.1+, scipy, opencv, scikit-image; no models. Modern ComfyUI required (frontend ≥ 1.37, base ≥ 0.12), same as every node in this pack.