Finally, I found a duplicate finder to remove my duplicate photos. I got 3.8 GB photos in my photos library, hundreds of them are duplicate. I tried 3 duplicate remover tools, none of them helped delete most of the duplicates. I was so disappointed, Cisdem Duplicate Finder was my last try, to my surprise, it removed and easy to use. Now, I get more space on my mac and feel relaxed to store all the photos to my mac, because I have enough time and space to pick my favorite photos later.