How to Overlay Images in the Browser with Canvas

Overlaying one image on top of another is a common task in web development.

You might need it when building a watermark tool, a simple image editor, a product preview feature, or a quick design workflow where users can place a logo, sticker, or transparent PNG on top of a base image.

In this post, I’ll walk through a simple way to overlay images in the browser using the Canvas API.

Common use cases

Image overlay is useful in many small but practical scenarios:

Adding a watermark to an image

Placing a logo on a product mockup

Combining a transparent PNG with a background image

Creating simple social media graphics

Previewing how one image looks on top of another

Building lightweight browser-based image editing tools

If you want to build this feature into your own web app, Canvas is a good starting point.

Basic idea

The core idea is simple:

Create a canvas element

Load the base image

Draw the base image onto the canvas

Load the overlay…