The popularization of digital cameras has led to an increasing number of repetitive, similar photos stored in our computer, and this problem is exacerbated by the rapid progress of mobile camera. Because in order to get a satisfying picture, we may take dozens or even hundreds of photos to choose from. This ends up filling our computers, phones and digital cameras with a mass of duplicate photos that should have been deleted. Not only does this lead to a huge waste of disk space, but more importantly, it makes photos become so chaotic and harder to manage.