How to apply FILE in views field
When you create a new view, you can choose on which entity the view is based on. In the first picture the view is based on File, in the second picture it is based on Content (nodes). 

You only see the fields of that source you have selected.

Another method to get the fields from File would be to configure a relationship using a reference field. But this is then additional, you get fields from both tables by doing this.