# Image overlay

The image overlay feature lets you overlay an image on top of a pane, or show it and your site side-by-side. With this you can quickly compare a site to the design or to [earlier screenshots](/docs/making-screenshots/) to detect visual regressions.

If a image overlay is shown, the icon will show a blue dot.

The image overlay has two modes:

*   **Overlaid** shows your site with the image overlaid on top of it. You can apply various filters, and fade between the image and the side. It also has a split view.
*   **Side-by-side** shows your site and the image next to each other. This mode is only available in the [horizontal and vertical layouts](/docs/layouts/).

Read on for more info on the two modes.

## Setup

Add a image overlay by clicking the icon in a pane header.

Once you've selected an image, the pane will automatically resize to the width of the image overlay.

From here, select if you want to show the image overlaid on the site, or side by side, and set an X and Y offset to position the image where you need it. the X and Y offset are number fields that you can increase with the arrow keys. Hold ⇧ while pressing the arrow keys to increase the offset by 10, and hold ⌘ while pressing the arrow keys to increase the offset by 100.

### Removing the image overlay

To quickly remove the image overlay, click the icon in the pane header using your middle mouse button. Alternatively, click open the settings and click "reset".

### Troubleshooting

The image overlays is synced with the main scroller on the page, which you can find with `document.scrollingElement`. If your image overlay doesn't scroll along with your page, then you probably have a different scrolling area overwriting that scrolling element (for example, a 100vh height div with overflow:auto as the top element)

The scrolling element is the designated scrolling element for the page (usually just the `html` element) and it's optimized compared to other scrollable elements, so it's the one you'll want to use!

## Overlaid Image

With the image overlaid you can see both the image and the website, letting you easily see where the differences are.

Use the slider to fade between the site and the image, or toggle "image overlay visible" to quickly hide and show the image.

There are three overlay styles:

*   **Normal** shows the image without any modifications
*   **Difference** sets the "difference" blend mode between the image and the site. Everything that's similar turns black, and differences are highlighted.
*   **Invert** Inverts the image. Everything that's similar turns grey. The differences from the image are shown inverted while the site retains its original colors.

### Split View slider

The overlaid image has a slider on top of your pane so you can scrub between your site and the image. Useful for when you need to compare small details between the two.

## Side-by-side image

This shows the image to the right of your pane, while syncing the scroll position so you can compare them side by side. You can disable the synced scrolling from the settings to scroll both individually.

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