1hew-ComfyUI-1hewNodes/web/docs/1hew_MultiImageOverlay/en.md

Multi Image Overlay - Sequential Layer Compositing

Node Purpose: Multi Image Overlay overlays multiple image layers sequentially. RGBA inputs use the alpha channel for normal layer compositing, while RGB inputs are treated as opaque layers. If any input contains alpha, the node processes everything in RGBA and automatically outputs RGBA. Supports dynamic input ports image_1..image_N and multiple fit modes.

Inputs

Name	Port	Type	Default	Range	Description
fit_mode	-	COMBO	center	top_left / center / stretch	Size fitting mode.
color	-	STRING	1.0	-	Legacy background color parameter kept for compatibility; when any input has alpha, the node outputs RGBA directly.
image_1..image_N	-	IMAGE	-	-	Dynamic image layers where image_1 is the topmost layer and larger indices go further down.

Outputs

Name	Type	Description
image	IMAGE	Batch of composited images.

Features

• Dynamic ports: inputs starting with image_ automatically expand; image_1 is the topmost layer and larger suffixes are placed further below.
• Size alignment: uses the bottom-most image dimensions as the base canvas size.
• Channel rule: if any input has alpha, all layers are composited in RGBA and the output automatically keeps alpha.
• Fit modes:
  • center: centers the overlay, cropping excess and leaving gaps transparent.
  • top_left: aligns the overlay to the top-left corner.
  • stretch: stretches the overlay to match the canvas size.
• Alpha compositing: correctly handles premultiplied alpha blending for RGBA images. RGB images are treated as fully opaque.

Typical Usage

• Image compositing: overlaying multiple elements with transparent backgrounds (e.g., stickers, watermarks, foreground subjects) onto a background image.
• Batch overlay: supports batch processing; broadcasts smaller batches to match the maximum batch size.

Notes & Tips

• Higher-numbered inputs are better suited for background/base layers, while image_1 is better used for the top layer.
• To keep transparency for downstream nodes, make sure at least one input already carries alpha.