➡️ Image Passthrough (FSL)

Here's a node with the most honest description in the pack: it takes an image in and gives you the exact same image back. FSL Image Passthrough is a stub - return (img_in,) is the entire implementation. No processing, no conversion, no side effects. Which raises the obvious question: why does this exist, and should you use it?

What it's actually for

ComfyUI lets you drag wires around freely, so a pure passthrough isn't strictly necessary. But it has two real jobs:

1. Organizational. In a big graph, a passthrough labeled clearly lets you route a wire through a tidy lane instead of dragging it across the whole canvas. Think of it as a visual waypoint - you can name it whatever you like in ComfyUI, so it doubles as a comment with an actual wire through it.
2. Breakpoint / branch point. When you're iterating on a workflow, inserting a passthrough gives you a clean place to disconnect and reconnect - a manual switch that costs you nothing. Some people also use it as a workaround for certain node-execution quirks where a direct connection bypasses a node you wanted to force to run.

That second one is the honest reason these stubs persist in packs. Every serious node collection has a "useless" identity node, and they get grabbed more than you'd think.

The inputs and outputs

• img_in (IMAGE) - required.
• img_out (IMAGE) - returned untouched.

That's it. One in, one out, no options, no settings, no API calls. It's fully local and costs nothing to run.

Should you use it?

Honestly? Most people won't need it. ComfyUI's native "reroute" node does the same organizational job, and stock reroute is cleaner if it's already in your toolbar. Reach for this one if you're already using the FSL pack and want a passthrough that (a) is obviously an IMAGE (it can't be accidentally converted to a different type like reroute can), and (b) sits in the same FSL Nodes category as the rest of your graph. If you inherited a workflow that has it, leave it - swapping it out is pure churn for zero benefit.

Install

It ships with the pack, so the install is the pack install:

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

or ComfyUI Manager → "ComfyUI FSL Nodes", then restart. No models, no key. This is the cheapest node in the entire pack to adopt - the only thing it can possibly do wrong is nothing, which is the point.