MIT explains…

It seems that the weirder — or more surprising — the better. If you test humans to see what photos we remember, and then feed those results into a neural network, you can train a computer to find the most memorable photos.
The least memorable photos have few defining characteristics such as photos of fields, lakes and buildings like many you have seen before.
A few things that can make a photo memorable
A few things that can make a photo memorable
- Unusual angle
- Odd facial expression
- Anything surprising
- Something that breaks the rules
- An image that tells a story
- Something threatening