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.
Bynder - Bynder is a cloud-based digital asset management solution for marketing professionals looking to simplify how they manage digital content via one central portal.
digiKam - Professional Photo Management with the Power of Open Source
Frontify Style Guide - Create beautiful web-based brand manuals in minutes
Flickr - image and video hosting website
Brand.ai - Create a style guide & integrate with Sketch, Slack, & Gulp