The use of photo summarization technology to summarize a photo collection is often oriented to users who own the photo collection. However, people's interest in sharing photos with others highlights the importance of cognition-aware summarization of photos by which viewers can easily recognize the exact event those photos represent. In this research, we address the problem of cognition-aware summarization of photos representing events, and propose to solve this problem and to improve the perceptual quality of a photo set by proactively preventing misrecognization that a photo set might bring. Three types of neighbor events that can possibly cause misrecognizations are discussed in this paper, namely sub-events, super-events and sibling-events. We analyze the reasons for these misrecognitions and then propose three criteria to prevent from them. A combination of the criteria is used to generate summarization of photos that can represent an event with several photos. Our approach was empirically demonstrated with photos from Flickr by utilizing their visual features and related tags. The results indicated the effectiveness of our proposed methods in comparison with a baseline method.