What do you mean "a licence to be able to host your work"?
It’s a tricky thing with copyright law. Basically, websites need to request a “non-exclusive license” in order to be able to display your content. If we weren’t granted that license, then an artist could theoretically upload their work, and then sue us for making alterations.
The alterations, of course, would be things like displaying a thumbnail of the work!
The license is non-exclusive in that the creator can take it back and grant that same license to any other website whenever they please. We’ll have a plain-language translation for the legalese of the license so that it’s understandable!