Image Tile Checker (CRT)

Image Tile Checker (CRT) answers one question: does this image actually tile? You feed it any image, and it returns that same image laid out in a 2×2 grid - the source repeated twice across and twice down. What you're looking at is four copies meeting at the seams, which makes even a subtle vertical or horizontal discontinuity obvious the way a single image never will.

Why would you care? Because a huge slice of production ComfyUI work is tiled. Tiled upscaling (the "more detail at arbitrary size" rung of the upscaling ladder), texture synthesis, seamless background tiles, even the per-tile detail passes that nodes like Image Upscale Sampler (CRT) run internally - all of it assumes the tile edges agree with each other. A texture that looks fine on its own can fall apart the moment it repeats, and that failure is a nightmare to spot in a single still. This node is the two-second sanity check you run before you commit to a tiling workflow.

The mechanism is trivial, and that's the point. The node concatenates the input tensor with itself horizontally, then repeats that row vertically - a pure torch cat on each axis, no resizing, no color shifts, nothing that could mislead you. What comes out is exactly your image at exactly its native resolution, just four copies. If the seams are invisible, you're tiling clean. If you can see a line, a brightness step, or a hard color break, you've found your problem before it wastes a render.

There's a single required input, image, and a single IMAGE output. Wire the output into a preview node (Preview Image) and look at the boundaries. Since it does no resizing, it's also fine to keep in a live graph as a permanent inspection tap - it's cheap enough that you don't need to remove it when you're done.

It's a one-purpose node and it doesn't pretend otherwise, but it's the kind of thing you reach for constantly once you start building loop-ready or tile-based workflows. Install with the pack: ComfyUI Manager → search "CRT-Nodes", or clone https://github.com/plugcrypt/CRT-Nodes.git into custom_nodes and restart. No models, no extra dependencies - it's torch-only, so it loads even if the pack's heavier optional requirements aren't installed.