Importing research, images, and web pages into Scrivener is handy, but sometimes creating a reference might be a better option. When might you want to use a reference instead of importing?
When you always want the most up-to-date version of a file or web page.
When you import a file, Scrivener creates a copy of it, thus freezing it in its current incarnation. Sometimes that’s desirable, other times not.
If the file is large or you have a lot of them.
Importing files increases the size of your project, which can slow down backups and syncing with online drives. A large project may take up too much space on a flash drive or be too big to email. Some people also prefer not to have their Research folder cluttered with anything but the most important reference materials.
When a web page doesn’t import well.
If you’re having trouble importing a web page, a reference lets you create quick access to it.
When you don’t need to refer to the item frequently, but want to be able to find it easily.
You can create internal references that point to items within the project (usually as document references, see below), but I’m going to focus on external references in this post. External references point to items outside of the project, located either on a drive accessible by your computer, or a web page.
more here - References in Scrivener | The Edited Life.