The main difference between a page and page resources is that page is an independent document, while a page resource is a helping document that cannot function on its own. For example, a layout cannot function on its own, but it gives structure to a page.
You can add the following page resources:
2 Adding Page Resources
To add a resource document, do the following:
In the App Explorer, right-click the module or a folder you want to add a resource to and select Add other:
Select the document you would like to add to your app.