Google has a cloud photo management system - Google Photos - which some consider to be the current best solution available.
This week Google has added the ability to create 'shared albums' - where multiple people can contribute images into a single collaborative album.
This could be rather useful! Imagine a team of teachers or students using a single album to curate photos from a trip or experience. It works online and via the Android and iOS Google Photos apps. As as a 'Google Apps for Education' user you have unlimited storage.
Google Photos can be found by clicking on the 'waffle' in the top right hand corner of any of the Google apps. Once you have started to create an album you can then choose the sharing options and choose how the album is shared and who can contribute to it.