Only members can create personal albums not you so not really a way you can do this. You can set in edit categories permissions to upload to cats etc but if you remove all rights to upload to any cat you might end up confusing your users alot
It is a placeholder category where all photos can be shown.
Your members can upload to their albums like stated but not all members are going to create albums cause this is what they do not you. You create categories to upload to. You can disable the members gallery from displaying and uploading to it with permissions but you need to have other categories to upload to.