photo import frozen

I attempted to import photos from my iPhone with airdrop. I went to my imported files folder, highlighted the photos and moved them to Photo. I had imported other photos from my digital camera via cable. All these photos appeared in Photos last import in album category, but the page is frozen. I cannot get back to photos category. I have to commandQ to get the open "last import" page, and Photo, to close.

I have restarted my Macbook pro,[ El Capitan, 10.11.6, 2.6 GHz Intel Core i7, 8 GB 1600 MHz DDR3] but the imported photos are again frozen on the opening page of Photo. Obviously something is wrong. These photos are not yet backed up.

Suggestions please to restore my app, and get my other photos back.