Did you look for the photos in "My Drive" or just "Drive"? Somehow I speculate that you unknowingly save said photos to your drive and you were able to pull them up on your computer. I have a similar setup with my Droid and chromebook. If I want easy access to files or photos between my mobile and lap top I can save items to my drive and likewise with photos in google photos. I don't know if this will help you but its a thought.