Dropbox is now as much a part of my work experience as my Mac, so naturally it would be great to put a Photos for OS X library into a Dropbox folder to create an off-site backup that I wouldn’t have to think about.
However, that’s a bad idea. Brian Webster at Fat Cat Software (who created iPhoto Library Manager and the new PowerPhotos applications) wrote a blog post about exactly why it’s a bad idea (spoiler: Dropbox syncs files and Photos tracks everything in SQLite databases, leading to corruption). Read the details here: Don’t store your photo library on Dropbox.
Jeff Carlson | Never Enough Coffee Creations 