Image Compare A/B 🆎

You've just re-run a workflow with a slightly different prompt, LoRA weight, or sampler setting, and now you need to know: did it actually change anything? Side-by-side previews fail you here - your eyes bounce between two canvases and your brain smooths over the difference. Image Compare A/B 🆎 puts both images on one panel so the change has nowhere to hide.

It's the AusBoss pack's answer to a problem every graph eventually hits, and it does exactly two things, both well.

How it works

Feed it image_a (your baseline) and image_b (the new render). The panel shows one picture; sweep your pointer across it and B is revealed up to the seam - like a wipe in an editing suite. There's also a hold mode where pressing flashes B over A in place. The way you catch a small change is flicking between them in place, and the panel makes that frictionless instead of making you re-arrange windows.

Nothing is drawn over the image itself; the resolution readout sits centered beneath it, so what you see is what you're comparing.

The one detail that makes this node worth having mid-graph rather than as a final viewer: image_a passes through the output unchanged. So you can drop it between an upscaler and your save node, compare against a reference branch, and downstream nodes keep working while you look. No rewiring to tear it out later - it's a pass-through with a viewing room attached.

What you set

Honestly, not much. Two required inputs (image_a, image_b), no optional parameters, one output (image_a, the passthrough). The node is marked as an output node, which is why it behaves as a preview surface, but the passthrough means it never has to be the end of a branch.

The only real quirk: it previews the first frame of each batch. Feed it a video batch and you're comparing frame 1 of each, not the whole clip. If you're comparing a specific frame, pull it out first with a frame selector.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/ausboss/ComfyUI-AusBoss.git

Restart ComfyUI and search for AusBoss (Manager: search the pack title, ComfyUI-AusBoss). No extra Python dependencies - the pack uses only Pillow, NumPy, and Torch already shipped with ComfyUI, and declares a minimum of ComfyUI 0.27.1.

Troubleshooting

If the seam wipe isn't revealing - or is revealing nothing because both images are identical - check that you actually connected two different branches. It's an easy thing to wire A into both inputs by accident. And if the images look the same size when they aren't, that's the panel centering the resolution, not stretching: if dimensions differ meaningfully, the images are scaled to fit the panel, so use the resolution readout, not the visuals, to judge size changes.