iSyndica is a great platform for everyone who sells to microstock & stock footage sites (and soon vectors) online. You upload your content once and you can then distribute it within seconds to all the channels. This make it easy to add several smaller channels or distribute very large stock footage to 4 or 5 sites.

Other benefits: cloud based storage/backup, analytics around your sales, upcoming promotional features. It will keep on improving over time. Feel free to message me with any questions or feedback.