More of a photo 'syncing' tool than a full-blown storage solution
Dropbox was built first on desktops and its mobile photos experience can be dreadfully slow
Perhaps the best approximation of a desktop photo library
Flickr remains a top-notch experience for serious photographers
Feels like it's built for storing files, not photos
Plenty of features, but more focused on videos than on photos
Google is more interested in you sharing your photos than simply storing them
It's a site created by professionals, for professionals
While it’s not perfect, cloud storage is finally a reality