Configuration is on a per-field basis. So to configure this module, you must visit the "Manage Fields" tab for your content type (or taxonomy terms, comments, etc.) By default, all fields on all file types are displayed. If you want to make things like "description" and "alt text" global instead of per-usage, you should disable the built-in description and alt text fields and use those provided by a file type instead.
PierAntonioGaspari: