Dezoomify is a terrific project by lovasoa that lets you download full-resolution versions of zoomable images — the sort you often find on museum, library, and other archival websites. Because these images are massive, the sites often present them via smaller image tiles that are stitched together in real time. Dezoomify helps you unite all those tiles into a single downloadable image.
There's also a dezoomify Chrome extension that handles a key part of the process: detecting the exact url of the zoomable image on a given webpage so it can be handed off to dezoomify to process. (It's also available for Firefox.) Unfortunately, the extension hasn't been updated in years and still uses Chrome's outdated Manifest V2, meaning it's been removed from the Chrome Web Store and unavailable for users without using some workarounds (which are themselves going away).
All this version of the dezoomify Chrome extension does is update it to Manifest V3 so it can be used again in Chrome and other recent Chromium browsers. (It just involved converting background scripts into service workers, adding some process IDs, and updating click handlers.) The original README from lovasoa is below.
This project is a browser extension for detecting zoomable images in web pages and downloading them with dezoomify. It works with the websites of many different museums, art galleries, libraries, and numerous other sources.
- Install the extension
- open a zoomable image in your browser
- click the grey magnifying glass icon in the address bar (
) - the icon should become blue (
), denoting that the extension is now actively listening for zoomable image requests - zoom into the image or reload the page
- if the extension detects zoomable images, you should see a small badge appear over the icon specifying the number of images found
- click the icon to open the image in the dezoomify website
- click "dezoomify", and wait while the image downloads at maximal resolution
- right-click on the downloaded image, and choose "Save As" to save it as a PNG file on your computer
See the illustrated guide with screenshots
As stated in its documentation, dezoomify may fail with very large images. In this case, you can still use this extension to find the zoomable image address, and then use dezoomify-rs instead of dezoomify to download the image. When the extension opens a new tab with dezoomify, don't click Dezoomify!, but instead copy the image URL, open dezoomify-rs on your computer, and paste it.
You can install this extension from your browser's official plugin market :
- for Firefox, see dezoomify on Mozilla Addons
- for Chrome, see dezoomify on the Chrome Web Store ( Unfortunately, google takes several weeks to review extension updates, so this version is usually less up-to-date and has more bugs than the firefox one )
You can also download the extension and install it manually in developer mode.
When you click on the extension icon (the magnifying glass), it starts intercepting all network requests coming from the site you are currently on.
When a request to a zoomable image (based on a set of URL patterns) is found, it shows a little badge in your address bar, which you can click to download the image with dezoomify.
For more information about dezoomify, see the dezoomify readme.
You can read dezoomify's Frequently Asked Questions. If you think you found a bug with the extension, or want to suggest a new feature, you can open a ticket here.
This browser addon requires the following permissions:
- Access your data for all websites: needed to intercept the requests that pages make, in order to look for zoomable images inside them
This addon is a free software (see LICENSE). You can see its source code at: https://github.com/lovasoa/dezoomify-extension/