Deku - Functional view library for building UI components as an alternative to React
ACDSee - ACDSee is an image viewer that uses very little system resources, and it has a small, sleek size that won't take up much space on your system.
Preact.js - Preact is a fast 3kB alternative to React with the same modern API. Components & Virtual DOM.
digiKam - Professional Photo Management with the Power of Open Source
Glimmer - Fast and light-weight UI components for the web
Flickr - image and video hosting website