I plug my phone into my mac as I would with an iPhone, and indeed Photos says that it can find the device, however it doesn't show any photo thumbnails or give you any options to import the photos. Any suggestions?
You can use this soft :
Use this software to transfer photos and videos between your Nokia Lumia phone with Windows Phone 8 and your Mac computer or laptop with Mac OS
After that you can import your photos (stored on your computer) by using Photos.
Photos -> File -> Import ...