The main difference between overlaying and merging is layering: overlaying places one image on top of another with adjustable transparency so both are partly visible in the same space, while merging places each photo fully visible in its own section of a grid or row.
When you want an overlay instead of a merge
| You want to... | Use |
|---|---|
| Stack a logo or watermark on top of a photo | Overlay |
| Show a before/after in one shared frame with a blend effect | Overlay |
| Place two full photos next to each other, both fully visible | Merge |
| Build a grid of several photos | Merge |
How overlaying works
An overlay tool places your second image on top of the first at a chosen opacity, so lowering the opacity lets more of the bottom image show through. This is the technique behind watermarking, double-exposure effects, and semi-transparent text-over-photo designs.
Overlay vs. AI blending
A manual overlay keeps both images exactly as they are, just layered with transparency. An AI image combiner instead regenerates a new scene influenced by both images, which is a much bigger transformation than a transparency overlay.
Frequently asked questions
- What's the difference between overlaying and merging images?
- Overlaying stacks one image on top of another with transparency; merging places each image fully visible in its own section of a grid or row.
- Can I control how transparent the overlay is?
- Yes, most overlay tools give you an opacity slider so you control how much of the bottom image shows through.
- Is overlaying the same as watermarking?
- Watermarking is one use of overlaying: placing a semi-transparent logo or text on top of a photo.