Hello/Hi/Greetings,

Its great to have the User Colelctions plugin.
While you have given me an option to share my collection with someone, there is not way that person can also contribute to my collection.

I use piwigo for a social movement and we are 5 people who share admin responsibilities in 5 regions of the world. So while I create a collection, it would be useful, if you could my colleagues also to contribute to that collection, by adding photos of their choice from various albums.