📱 CR Thumbnail Preview

When you run a batch of 20 or 40 images, ComfyUI's default preview stacks them at full size and you're stuck scrolling forever. CR Thumbnail Preview fixes that: it shrinks a batch down and lays it out as a thumbnail grid - a contact sheet - right in the node, so you can take in the whole run at a glance. It's a preview-only node; it doesn't output anything, it just gives you a saner way to look at a lot of images at once.

The use case is triage. You generated a big sweep and you want to spot the two or three keepers without opening each one. A grid of thumbnails is the right shape for that, and this is the quick way to get it without wiring up an image-grid compositing chain.

How it works

You give it a batch of images, a rescale factor, and a column count, and it renders a downscaled grid in the node's own preview area. It's marked as an output node - a terminal leaf - so it ends the branch. Nothing chains off it; the point is the on-node display. rescale_factor controls how small each thumbnail gets (0.25 by default, so quarter-size), and max_columns sets how wide the grid runs before wrapping to a new row.

The inputs and outputs that matter

• image (IMAGE) - the batch to preview. This is the whole input.
• rescale_factor (0.1–1.0, default 0.25) - thumbnail size. Smaller = more fit on screen; larger = more detail per thumbnail.
• max_columns (default 5) - grid width. Set it to match how many you want per row.

Output:

• show_help - a wiki link. There's no image output - this is a display-only node, so don't go looking for something to wire onward.

How to install it

Comfyroll Studio (Suzie1 and RockOfFire), a mature utility pack - no models, no heavy dependencies.

• ComfyUI Manager - search Comfyroll Studio, install, restart.
• Manual - cd ComfyUI/custom_nodes && git clone https://github.com/Suzie1/ComfyUI_Comfyroll_CustomNodes.git, then restart.

Also on CivitAI.

Common issues

The most common "problem" is expecting an image output - there isn't one. This is a preview node, full stop; if you need the grid saved as a file, use a dedicated image-grid or save node instead. Also note the input wants a batch - feed it a single image and you get a single thumbnail, which rather defeats the purpose.

As a Graphics node, it rides the pack's graphics import path, which is the one most prone to failing. If it won't load, your log shows Comfyroll Studio: Failed to load Graphics nodes and then NameError: name 'CR_HalftoneGrid' is not defined. The NameError is a symptom - a real import error higher up, almost always an incompatible Pillow (PIL) version pulled in by another custom node, took the graphics group (and often the whole pack) down. Reinstall Pillow (pip install --upgrade --force-reinstall pillow) into ComfyUI's Python and restart.