About the permission problem I've solved testing on a new environment. Maybe something misconfigured, but I'm not able to find what... I've checked everything. In my new environment anyway it works fine, so this part is solved for me. Now the other question...
krileon wrote: You can change the owner by editing the media after upload, but there's no way to change it beforehand for the gallery tab or gallery field usages.
About the owner I've thought that I could use an auto action to automatically change the owner ID from the ID of the user to the ID of the super admin.
Is it possible? If it is possible could you please suggest me step by step how to configure the auto action?
Thanks in advance.