I have several large databases of lantern slides that I created in an earlier version of FileMaker (Pro 9). When I tried to convert the database to the new version of FileMaker running on Mac Sierra, I discovered that FileMaker's "Insert ... Picture ..." can't see the subfolders in Photos Library, probably because they are hidden by definition in the Finder. I have tried various scripting options with the path to direct the program to the appropriate folder, but none of these works. By contract, all the Microsoft applications (Word, Outlook, etc.) *can* see the individual photos that reside in the Photos Library, so this is clearly something that can be programmed into an application.
As a workaround, I have stored all my photos in a separate folder and imported them into Photos as thumbnails, but this is a clumsy alternative.
If anyone has figured out a way to do this, I would be glad to hear about it. Otherwise, I hope the developers will correct this problem in an update.