I really like the app but while this explains how app works, 3 years after this comment, I still find it is awkward.  It would be much more helpful to have a setting so the user can specify whether files should be displayed new to old or old to new. 

Also I had to discover that "select all" pick was for screen only not all photos in the folder.  pick should specify range being selected and have a select folder pick to choose all photos in the folder.