SpectraSort is a photo-sorting app for iPhone with 3 review piles: Picked, Kept, and Discarded. The middle pile matters. A photograph can belong in your library without being one you want to share or put in a highlights album.
Choose a tool such as Best Shots or Find a Subject, narrow the input to an album if needed, then review the ranked results. Pick a photograph by swiping right; down keeps it, and left discards it. Similar images can appear in stacks, with the final Batch Actions screen assigning an action to each pile. The screen explicitly says nothing applies until you tap an action, giving the sorting decisions a separate checkpoint before anything gets deleted.
I'd start with one album. An October US App Store review reported Best Shots getting stuck while preparing the review screen, along with the phone locking during processing. November release notes mention fixes, but don't identify that particular failure as resolved. The developer's explanation of stacking makes the intended workflow clear; it isn't evidence that every library completes it reliably.
The review piles suit iPhoners who want an initial shortlist and still want the final say. Check a manageable batch before trusting a large cleanup.
