Today, images and video are everywhere. Online photo sharing sites and social networks have them in the billions. Search engines will produce images of just about any conceivable query. Practically all phones and computers come with built in cameras.
It is not uncommon for people to have many gigabytes of photos and videos on their devices.
Programming a computer and designing algorithms for understanding what is in these images is the field of computer vision. Computer vision powers applications like image search, robot navigation, medical image analysis, photo management and many more.