Hello and welcome to the forum,
Don't understand quite well your question. Every background (each slide has a background image) can be found in the Library that is saved within the cptx-file (think you are talking about Automatic capture). Use right-click menu to find the background of a slide, and in the Library you can use the right-click menu to Edit the background with your preferred graphical application.
But File location: can be specified in Preferences, first screen.
Lilybiri