What are some alternatives?
Piwigo - The default home page of a Piwigo photo gallery is the list of root albums. If it doesn't fit your need, you can create your own customized home page. There are 2 main methods: either you create an additional page or your create dynamic blocks.
Instagram - Instagram is a mobile, desktop, and Internet-based photo-sharing application and service that allows users to share pictures and videos either publicly, or privately to pre-approved followers.
Lychee - Lychee is an open-source, free software program for self-hosted photo management. It can be installed on the user's own server or website. The software permits the uploading and management of photos and also makes sharing photos very easy.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
Flickr - image and video hosting website
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.