Every time I go to import photos from my iPhone, Photos shows several hundred photos that have been previously imported as new. I've imported these photos before but Photos (and previously iPhoto) still thinks they're new every time. I've tried importing them again but the next time I go to import photos, they're there again as new photos, rather than showing in the Already Imported section. I could import them over and over and over again and they'd still show when clicking the 'Import All New Items' button. Any suggestions to get these ones seen as previously imported items, short of deleting them altogether?