What Is an Overlay Image? 5 Practical Ways to Use It

What is an overlay image?

An overlay image is a picture or graphic placed on top of a base image. The base sets the canvas, while the overlay can be moved, resized, or made partly transparent. Use an overlay to add a logo, place a smaller photo in a corner, or blend a texture across a background.

Two kinds of transparency can affect the result. A logo file with a transparent background shows the base around its letters, even at 100% layer opacity. Lowering the layer opacity fades the letters themselves as well. The W3C guide to alpha compositing shows how the colors from both images contribute where they overlap.

1. Add a logo or watermark to a photo

Use a product or portfolio photo as the base and a transparent PNG logo as the overlay. Keep the logo small enough that it leaves the subject clear. Give it a margin from the edge and place it on an area with enough contrast. A white logo may read well over dark fabric and disappear against a bright window.

Keep a brand mark at full opacity if readers need to recognize it at thumbnail size. For a subtle watermark, lower the opacity and check the result at the size people will actually see it.

2. Add a close-up to a thumbnail or comparison

Use a wide shot as the base and place a detail photo in one corner. A listing could show an entire chair with an inset of its upholstery. A tutorial thumbnail could show the finished object with a close-up of a join or stitch.

Keep the inset fully visible and use a thin border when the images have similar colors. Choose an area that leaves the main subject and any headline clear. For a before-and-after that gives both images equal space, use a side-by-side layout.

3. Blend in a texture or color tint

Layer paper grain, film dust, or a solid color graphic over a photo to change its mood. Start around 10–20% opacity and raise it until the effect is visible at the final display size. Check a bright area and a dark area, since texture can look stronger in one part of the same image.

Prepare a texture with the same proportions as the base if you want it to cover the whole image. A transparent texture can also add grain in selected areas while leaving others clear.

4. Preview a label or graphic on a product

Put a label over a straight-on photo of a box, or place a small illustration on a flat postcard mockup. Resize the overlay until it looks proportional and try a few placements before settling on one. This works especially well when the target surface faces the camera.

Use a perspective or warp tool when the graphic needs to follow the angle of a tilted screen or wrap around a bottle. A simple overlay is useful for deciding on the size and placement before making that more detailed mockup.

5. Add callouts to a screenshot or guide

Layer a transparent arrow, numbered badge, or highlight graphic over a screenshot. Place it close to the button or field the reader needs, and use a second overlay if another part of the screen needs attention. When the screenshot also contains private details, redact those areas before sharing the finished image.

How do you overlay an image online?

Open the Overlay Image editor to follow these steps with your own files or try the sample images first.

1. Choose the base image first. Crop it beforehand if the result needs to match a specific aspect ratio.
2. Add your overlay, drag it into position, and resize it until both images read clearly. Repeat for any additional graphics.
3. Adjust opacity and add a border if the edges of a small inset need more definition. Preview the result at the intended display size.
4. Download a PNG to preserve transparency in the finished image, or a JPG for a finished image with a solid background.

Frequently asked questions