Image Compare

Eyeballing "did this upscale actually help" or "is the inpaint blending in" by flipping between two separate Preview Image nodes is annoying - your eyes have to jump, and subtle differences hide in that jump. Image Compare fixes it the obvious way: feed it two images and it gives you an interactive slider, right there on the node, to drag between them.

Worth knowing going in: this exact idea - an A/B slider preview node - shows up in more than one pack. rgthree-comfy ships an Image Comparer as part of its general quality-of-life toolkit, and there are standalone single-node packs that do nothing else. None of them are wrong; if you've already got Link Comfy Nodes installed for one of its other utilities, this is the free one that's already sitting there.

How it works

Two images in, one draggable divider out - literally a slider you pull left and right over the node to reveal more of image A or image B. It's a viewing tool, not a processing one: nothing gets modified, blended, or saved. Its entire value is letting you see a difference instead of squinting between two windows.

The inputs and outputs that matter

• image_a (IMAGE, required) - typically your "before."
• image_b (IMAGE, required) - typically your "after."

That's the full input list - no threshold, no blend mode, no diff-mask output. It's deliberately minimal. And there are no outputs: this is a terminal node, same as most preview nodes in this pack, so nothing chains off it. If you need the images passed further downstream too, tap the wires before they reach this node.

How to install it

Through ComfyUI Manager: search "Link Comfy Nodes," install, restart. By hand:

cd ComfyUI/custom_nodes
git clone https://github.com/Mister-Link/link-comfy-nodes
pip install -r link-comfy-nodes/requirements.txt

Restart ComfyUI afterward.

Common issues & troubleshooting

Expecting a difference mask or blend modes and not finding one. If you need more than a visual slider - an actual pixel-diff output you can threshold or feed somewhere else - this node isn't it, and it isn't trying to be; that's a different, more analytical tool. This one is purely for your eyes.

Mismatched dimensions between A and B. Comparing an original and a resized/upscaled version side by side is exactly the use case, but if the two images are wildly different resolutions the slider comparison gets visually meaningless fast - the "before" and "after" won't line up spatially even if the content matches. Normalize both to the same size upstream if you're doing an actual quality comparison rather than a rough sanity check.

It disappears in a busy graph. Like Fast Image Preview and the other preview nodes in this pack, it's an output node with no downstream connections, which means it's easy to lose track of visually once your graph has thirty nodes in it. Grouping your preview nodes together, or bookmarking them if you're also running rgthree-comfy, saves a lot of scrolling when you're trying to actually look at a result.