What is 'real time' in a Computer Vision context?
There is no one answer to this question. "Real time" can mean very different things, depending on what kind of sensor or sensors you are using, and what you are trying to do. By the way, editing and storing images may not even qualify as computer vision. Computer vision is about extracting information from images or video, and the meaning of real time depends on the kind of information you are trying to extract. 

A typical video camera acquires images at 30 frames per second (fps). So that can be your definition of "real-time", i.e. being able to process images at the rate at which you acquire them.

On the other hand, if your goal is to detect and track objects in videos, then "real-time" is a function of how fast those objects move. For example, 10fps is often sufficient for tracking people walking on the street, but probably not for tracking cars going 70 miles per hour on a highway.