This app was mentioned in 2 comments, with an average of 1.50 upvotes
Yes it caches the photos. You can clear cache of app by going to app settings.
Also i have a recommendation of an app that has muzei plugin Quisque :- Photo Scanner and Photo Editor https://play.google.com/store/apps/details?id=com.quisque Amazing app with lots of features included Muzei.
Here is the solution which lets you scan unlimited times and its free of course :)
Quisque :- Photo scan and Editor https://play.google.com/store/apps/details?id=com.quisque
I love this app.