Murder mystery : can you solve this

Hey intelligent steemians! This beautiful lady was killed by her husband. The guy loved him so much. Few months back he had gifted a smartphone to his loving wife on her birthday. He came to home on her birthday without informing her just to surprise her and took a picture of her with this smartphone.
One day he was looking that picture, suddenly he saw something in the picture. He went to the home and shot his wife. After that he surrendered. Being asked by the cops he gave that picture to cops. Cops saw that picture and found the reason.
Now, can you find out the reason? What was in that picture and why he killed his wife?
Try to figure out and upvote and comment.