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Explore Historical Images through the Library of Congress Free to Use Browser Extension

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This is a guest post by Flynn Shannon, a Junior Fellow in the Library of Congress Office of Communications.

Before coming to the Library of Congress as a Junior Fellow I had no concept of how large or varied its collections are. Over 167 million items are kept at the Library. Of these, more than 24 million are books. That leaves around 143 million more things. Included in this number are such effects as George Gershwin’s piano, the contents of Abraham Lincoln’s pockets the night of his assassination, and more contemporary content such as web comics.

During my time at the Library, I focused on the over 1 million images available digitally, anywhere in the world. Specifically, I was tasked with designing and developing a proof-of-concept Chrome browser extension to increase awareness and interaction with digital images with no known copyright restrictions. These images are of particular interest because they can be used freely for any purpose. Once installed, the extension will change the background of each new tab to a random picture from the Library’s collections that is free to use and reuse. The extension will encourage the use of these images by giving users the option to easily download, email, and share the photos on Facebook and Twitter. Users will also be encouraged to learn more about the items by interacting with them on the Library’s website. By clicking on the title of any image, the user will be taken directly to the item’s page on Similar extensions have been created by Europeana, The New York Public Library, and MappingVermont.

The Process
My first step was to make a manifest.json file. This process is documented in the .zip file, which you can access on the Free to Use Browser Extension experiment page.

I was able to use a field called “chrome_url_overrides” to replace the default new tab with a custom web page built like any other using HTML, CSS, and JavaScript.

basic user interface
Basic user interface of the Library of Congress Free to Use Browser Extension.

Once I had finished the front end, I needed pictures for the background. After reading reviews of similar extensions I noticed that the most common complaint was that there weren’t enough unique images. Soon after installing, users began to see the same pictures over and over. Because of the size of the Library’s collections of digital images, I hoped that this wouldn’t be a problem. The folks at LC Labs pointed me to some Jupyter Notebooks that made getting data from accessing bulk images on the Library’s website a breeze. I was able to create a method of getting the metadata I needed about each photo from their URLs by making only slight modifications to code found in the notebooks. My first inclination was to pull from all the photos available from the Library’s website. I quickly found some issues with this approach. I began to come across imagery containing offensive, negative stereotypes. Viewed in the proper context, these images provide an important look into a darker time in history. However, they were not appropriate for the purposes of this extension. In addition, not all of the photos online are without copyright restrictions.

As I began coming up with strategies to filter any offensive and copyrighted content, I had a meeting with the Library’s Prints and Photographs division. They recommended that I use the photos on the Library’s Flickr channel, which have no known copyright restrictions and are curated. Using a Python implementation of the Flickr API, I was able to find the URL of each image on the Library’s website. From there I used the previously created method to write a JSON file that is read by the client-side JavaScript to change the image displayed. The current version of the extension is pulling from a set of more than 16,000 images available on the Library’s Flickr channel (although the Library currently has more than 30,000 images on Flickr and adds more nearly every week).

This is a screenshot from the Library of Congress Free to Use extension.

free to use browser extension screenshot
Library of Congress Free to Use browser extension displaying an image from the Library with metadata and sharing options.


Try the Free to Use Browser extension yourself! You’ll find instructions for download on the Library of Congress Labs Experiments Page – add a comment to this blog post to let me know what you think.

Comments (11)

  1. A fun idea. I have installed, and I’m noticing that the initial image takes a long time to display, including the associated title. Advancing to the next image doesn’t seem to work, at least not quickly.

    • Thanks, Dean – we’ve integrated your feedback into the instructions!

  2. I love using the extension. I am surprised and delighted every day with the images I discover. (And it was great to work with Flynn this summer!)

  3. will this extension be made compatible with Firefox, PaleMoon, Opera or Brave

    • Thanks for your interest, PeterTx52. We will investigate making the extension available for other browsers, but for now we are just testing the Chrome version. Further enhancements / platforms will depend on various factors including available resources.

  4. Sounds great, but instructions did not work.

    • Hi Peter, can you share more details about where you ran into problems with the instructions?

  5. Fascinating using the extension to browse the images. Thanks for the fun tool. I found going forward and back mostly worked. One image I could not back up from. It is The Doughs, Tongland, Kirkcudbright, Scotland | 1890. I can go forward but not backward from it. Curious

  6. I’ve answered the question from my previous comment.
    When clicking on the image link that takes you to the LOC detail page and then a back arrow to return you can no longer backup past that page. A work around is to hold the ctrl key when clicking the link which opens the detail page in a new tab.

  7. This is great! I’m part of an LC Teaching with Primary Sources regional grant and will be informing our participating teachers of this Chrome Extension. You may want to consider sharing this with the other TPS grant recipients. I only discovered this because I subscribe to The Signal.

    • Thanks, Sarah! We’ll share your suggestions and the extension experiment with our Teaching with Primary Sources colleagues.

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