​Hello,
Thank you for your answer!

To be clear, I don’t want the categories “Video”, “Audio” and “Document.
I need to replace them by three other categories of Photos, to obtain Photo A, Photo B and Photo C.​

​Answers to your questions:
1/ Non, the users will be free to create as many galleries as they want.
2/ Yes, once my categories are created, they will suffice.

After several tries based on the documentation I found here https://buddydev.com/mediapress/topics/api-reference/core/media-type/mpp_register_type/, I was able to create the category “Presentation” using the code “​function mpp_custom_register_presentation_type” given in the documentation.
That’s exactly the result I want to get, but instead of a “Presentation” category, I want a “Photo” category where jpep,png,jpg files will be uploaded.

In this same documentation, there is another code : ” function mpp_custom_register_presentation_type_support”, and I don’t understand what is the use of this code.

Thanks for your help!