Image Composition

This means layering two images or placing them side by side.

In Photoshop, you'd just drag one image on top of the other, but doing the same thing in node-based ComfyUI takes some work.

You'll sometimes need it for things like inpainting, but just like with color correction, giving up and using a paint tool is also a perfectly good choice.

Overlaying Images

This simply places one image on top of another.

ImageCompositeMasked Node

imagecompositemasked.json

This is the basic node for overlaying images.

  • destination: The background (base) image.
  • source: The foreground (top) image.
  • x / y: Position, measured from the top-left corner.
  • resize_source: If set to true, the source image is stretched to the same size as the destination (Note: it will be distorted if the aspect ratio is different).

Centering the Image

imagecompositemasked_align_center.json

You can center it by doing coordinate math with nodes, like the familiar position: absolute; top: 50%; left: 50%; in CSS, but... well, honestly, it's a pain (；・∀・)

Overlaying Transparent Images

This is the key to layer compositing in ComfyUI.

If you want to overlay "an image with a transparent background," simply connecting the images won't work.

In ComfyUI, you have to think of it instead as "replacing the masked area with the source image."

Steps to Composite Transparent PNGs

imagecompositemasked_with_alpha.json

It's the same ImageCompositeMasked node, but this time you use the mask input.

  • 1. When you load a transparent image, you get a "mask of the transparent part" from the MASK output.
  • 2. Connect this mask to the mask input of the ImageCompositeMasked node.
  • 3. Then, only the masked part is replaced by the source image (e.g., pink sky).

Handling Distortion Due to Size Differences

If resize_source is set to true, the source image is forcibly stretched to the same size as the destination image.

imagecompositemasked_with_crop_pad.json

That's fine if the background is a solid color or a pattern, but a photo will end up distorted. The easiest solution is to pad/crop the two images to the same size in advance.

  • 🟪 Pad the foreground image to the size of the background image.
  • 🟨 Crop the background image to the size of the foreground image.

Practical Example: Combining with Segmentation

imagecompositemasked_segmentation.json

The same idea applies when you want to "change the color of just the dress."

  • 1. Create a "dress mask" from the input image using segmentation.
  • 2. Connect EmptyImage (solid color image) etc. to source.
  • 3. Set resize_source to true (a solid color doesn't care about distortion, so this is fine).
  • 4. Now only the dress is filled with the chosen color.

It may be hard to get a feel for at first, but you'll get used to it.

Stitching Images (Concatenation)

Joins images side by side or top to bottom. Handy for making comparison images.

Image Stitch Node

image_stitch.json

A simple stitching node.

🪢 Image Concatenate From Batch Node

image_concatenate_from_batch.json

You can line up 3 or 4 images by chaining Stitch nodes, but if you want to lay out a batch (a set of images) in a grid all at once, this node handles it neatly.

Mixing Images (Blending)

Image Blend Node

image_blend.json

It's like a layer's "blend mode" in paint software. Out of the box it can only do very simple blending, but you can adjust how strongly the images are mixed with blend_factor.

  • blend_factor: The closer to 1.0, the stronger the source image.

EmptyImage Node

emptyimage.json

A node that just creates a solid color image.

How to Set Color

Setting the color is a bit confusing: instead of the familiar hex code or RGB, you enter it as 24-bit color (a decimal number).

The calculation formula is as follows:

Decimal Value = (Red × 65536) + (Green × 256) + Blue

Example: If you want to create pink (RGB: 255, 192, 203)

255 × 65536 + 192 × 256 + 203 = 16,761,035

Enter the resulting value in the color parameter.