Preview Image (16 bit)

Preview Image (16 bit) is the "look, don't touch" version of Save Image (16 bit). Same 16-bit PNG writer underneath, but instead of dumping files into your output folder it writes to ComfyUI's temp directory and shows you the image in the UI. You use it when you're building a 16-bit pipeline and just want to eyeball a result mid-graph without littering output/ with test files.

It's genuinely thin - and that's fine, because it exists to be the boring, reliable preview half of a two-node pair. You'll wire your 16-bit IMAGE into this to check, and only switch to the real Save Image (16 bit) once the result looks right.

What it does

Under the hood it's the same pypng 16-bit writer as Save Image (16 bit), pointed at the temp directory with a random per-run suffix so previews don't collide. It also preserves your prompt and extra PNG info metadata through the save - the pack's author calls that chunk of code "extremely stupid," which is honest, but it works.

The only input

• images - the IMAGE you want to look at. No filename prefix, no settings, nothing else to configure. Wire it up, run, and the preview appears in the UI like any other preview node.

No outputs - it's an output node.

Installing

Same as the rest of the pack, and it needs pypng:

cd ComfyUI/custom_nodes
git clone https://github.com/city96/ComfyUI_ColorMod
cd ComfyUI_ColorMod
pip install -r requirements.txt

Restart ComfyUI, or install via ComfyUI Manager by searching "ComfyUI_ColorMod". If the node is missing from your menu, pypng isn't installed - check the console at startup for ColorMod's "Can't find pypng" message.

Gotchas worth knowing

• Your preview is still 16-bit on disk, but your screen is not. Monitors are 8-bit, so a preview can't show you the extra precision - what you're really checking is the tone/colors, not the smoothness. Trust the saved file (and viewing it in a proper image editor) for banding.
• Don't confuse it with the stock Preview Image. The stock one reads through the 8-bit path; this one keeps 16-bit precision in the file it writes. In practice, on screen, you'll struggle to tell them apart - the difference matters when the file itself is the deliverable.

It's a small node that does one thing, and for 16-bit workflows it's the right thing: preview cheaply, save deliberately.