Is there any way so that from an admin page someone can control the websites, for example, add new photos on the portfolio or so on without going into the editor?
Hello Flavi,
Yes there is a way using the user input section. You can create a form that allows users to input information that is stored in a collection, or even upload photos. And you can use these photos to be displayed elsewhere such as a repeater or dynamic page.
Here is more information on photo upload: https://support.wix.com/en/article/request-allowing-visitors-to-upload-files
Best of luck