Flickr - image and video hosting website
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.
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
digiKam - Professional Photo Management with the Power of Open Source
PhotoPrism.app - PhotoPrism® is an AI-Powered Photos App for the Decentralized Web. It makes use of the latest technologies to tag and find pictures automatically without getting in your way. You can run it at home, on a private server, or in the cloud.
Piwigo.org - Manage your photo collection with Piwigo. Piwigo is open source photo gallery software for the web. Designed for organisations, teams and individuals.