Professionals taking hundreds of contextual photos need to retroactively tag them efficiently. An app could auto-group shots by GPS clusters or time windows, then apply bulk descriptions.
Offer smart suggestions like "Conference Day 1" or "Central Park walk" based on movement patterns. Journalists would pay to save hours of manual sorting.
Start with iOS-only EXIF editing with basic clustering. The hard part is competing with built-in photo apps gradually adding similar features.