How to share photos from Photos.app to Flickr retaining title, description and tags? In the new Photos.app application, the export of photographs to other services is via the OS X extensibility feature. Sharing one picture to Flickr shows the picture's filename as the title and empty description and tags even though the pictures had these three fields filled in the 'Info' window. This metadata was exported fine with iPhoto which had its own sharing mechanism so this issue is either with Photos.app or with the extensibility feature of OS X. How can I upload pictures from Photos.app to Flickr without having to retype all the metadata for each one of them?
Nearly a year later you would expect Flickr integration to have improved. As of February 2016 I have the exact same experience. To investigate further I opened this forum thread:

https://www.flickr.com/help/forum/en-us/72157665235195925/