Easy Secure Photos (ESP) encrypts photos uploaded to cloud services so that attackers ‘ or the cloud services themselves ‘ cannot decipher them. Encrypting photos results in three black-and-white files, each one encoding details about the original image’s red, green, or blue data. At the same time, users can visually browse and display these images as if they weren’t encrypted. The researchers wanted to make sure that each user could use multiple devices to access their online photos if desired.
Source: https://www.helpnetsecurity.com/2021/07/21/image-encryption-technique/