It made no sense to have a file upload in each form that needs a media,
because to reuse an existing media users would need to upload the exact
same file again; this is very unusual and unfriendly.
A better option is to have a “centralized” media section, where people
can upload files there, and then have a picker to select from there.
Ideally, there would be an upload option in the picker, but i did not
add it yet.
I’ve split the content from the media because i want users to have the
option to update a media, for instance when they need to upload a
reduced or cropped version of the same photo, without an edit they would
need to upload the file as a new media and then update all places where
the old version was used. And i did not want to trouble people that
uploads the same photo twice: without the separate relation, doing so
would throw a constraint error.
I do not believe there is any security problem to have all companies
link their media to the same file, as they were already readable by
everyone and could upload the data from a different company to their
own; in other words, it is not worse than it was now.
jordi fita mas