Hi Lukas, at the moment this is not possible. in the near future we will support editing/uploading images and videos. Can assure you its on our roadmap.
8a Support: Can you inform everyone in one place (seperate topic) what is your "roadmap". What changes and when are you going to make to this webside ? People report a lot of problems or functionalities that are gone. It would be nice to know when you made the change not controling from time to time what happened.
Is it possible to add or change the discription of a picture?