Y7 Image Compare

You've got two versions of the same image - before and after an upscale, two seeds, an edit vs. the original - and you want to actually compare them. Dragging two preview windows around and squinting is miserable. Y7 Image Compare puts a draggable slider right on the node so you can scrub between image A and image B in place, like a before/after wipe in a photo editor.

It's a preview-only node from the Y7Nodes pack, based on Eses Image Compare by Eses Nodes. No outputs, no processing - it's a display tool, and a good one.

How it works

Two inputs: image_a (required) and image_b (optional). Wire them in and the node shows a combined preview with a draggable slider - drag one way to reveal image A over image B, and it updates live as you move. Two blend modes:

• normal - the slider wipes between the two images, side-by-side comparison style.
• difference - a blended comparison that highlights variations. This is the one you want when the images are nearly identical: differences glow, and identical regions look flat. It turns "did anything change?" into a visual answer.

The preview auto-sizes to the aspect ratio of the input images, and the node remembers your slider position and blend mode - they're saved with the workflow, and the preview even persists across workflow-tab switches. Right-click the image for Open Image / Save Image, which is a nice touch when you want to grab a still of the comparison.

Why it's useful

Two scenarios come up constantly. First, before/after work: inpainting, upscaling, color-matching, LoRA vs. no-LoRA - the difference mode makes the change unmistakable, which is exactly the "bit-identical unmasked pixels or not" question that masked inpainting workflows care about. Second, prompt/sampler comparisons: when two runs differ subtly, the wipe lets you find where they diverge instead of trusting your memory of what each looked like.

Because it's preview-only, it slots into any workflow without affecting the data flow - it's a branch you can hang off the end of the graph and ignore. There's no downside to leaving one in a shared template.

Installing it

cd ComfyUI/custom_nodes
git clone https://github.com/yushan777/ComfyUI-Y7Nodes
cd ComfyUI-Y7Nodes
pip install -r requirements.txt

Restart ComfyUI, or grab it via ComfyUI Manager → search "Y7Nodes". The comparison UI lives in the pack's web assets, so make sure the web directory installs along with the clone (it does by default).

Gotchas

The obvious one: no outputs means it can't feed anything downstream - if you expected to pipe the comparison result into a saver, that's not this node. Also, image_b is optional, so if you connect nothing it just shows image A (useful as a plain preview, but easy to misread as a bug). And like most slider comparisons, it works best when both images are the same size; if the dimensions differ, the resize behavior depends on the display logic, so matching resolutions is the reliable path. Nothing worse than that - it's a simple, well-behaved tool.