This extension is basically the official RSS feed for https://uhdwallpapers.org/ gallery.
If you wish to have a small button in your Chrome to know when a new wallpaper is featured just use it.
Almost all wallpapers are in 4K ultra HD 3840x2160 size.
All links are now secured (HTTPS).
A new look for the app was implemented and the thumbnails are fetched in the original size (400x225).