This extension adds a 'Seent It' icon to previously viewed Imgur gallery posts.
Imgur users asked for a feature to mark previously-viewed gallery posts for quite a while. This extension does just that.
If you use this extension, when you visit imgur.com, as you browse through the gallery, it will add the gallery post's ID to local storage. The extension then reads from the storage to mark posts as "Seent" (in basic terms, marked as "viewed"). It marks posts in the gallery list as well as the sidebar in individual gallery posts.
It currently does NOT handle reposts. That MIGHT be added in future development but it is currently not in the pipeline. I will try to keep this app up-to-date and update it with new features as time passes.
Because local storage can be in issue after quite some time, due to running on limited space (5MB), I am considering on adding in multiple options to handle marking images as "Seent", depending upon user feedback. They include: reading from History (searching only for imgur gallery posts), and a couple options for storing viewed gallery posts, such as using a file system to write to files on the user's HDD. I am also considering syncing options.
Feel free to view the code at either https://github.com/HHHApps/SeentIt or https://github.com/cowanhe/SeentIt. Also, if you use imgur, feel free to contact me on imgur.com at http://imgur.com/user/cowanhe.
About the permissions:
All of the code is available for the public to see, but I'll break it down as simple as I think I can. I encourage you to read through the code through the github links.
<all_urls>: This allows me to match each tab's url to "imgur.com" and "imgur.com/gallery/".
webNavigation: This allows me to track navigation from inside websites that change the data without refreshing the page. I only care about imgur.com.
tabs: This allows me to read the data from each tab you view, but I only care about ones with a url containing "imgur.com".
storage: This allows me to store Imgur's gallery IDs into the browser's local storage. This is the only reason I use this.