How can i lock the media upload for the other authors who are not assigned?

so i have role author . And one author cannot update the other author's document. But here you could see every field is close except for the Profile picture where we are uploading image in media.So now any author could go into other author's document and change the document's image.

How can i lock the media upload also for the other authors who are not assigned in the document?

P.S : I have a author field where i assign them from the document.