S Note - How do I change the default picture editor that is used to edit the cover?

[AC Question]

I have a Samsung Galaxy Note 10.1 (2014 edition). When I selected "Edit cover" for one of my S notes, after selecting a photo from Gallery, rather than selecting the app that I always use (QuickPic) to crop it, I accidentally selected the other editor option and set this as the default picture editor (not sure what this editor is, but it shows a white 3 x 3 grid on top of my photo).
How do I clear the current settings so that I can use QuickPic again?
I thought that I might be able to change the default under Settings/Application manager/App info, but I can't see how to do it from there.
Thank you if you are able to help.