Cinema-graphs are made by taking a series of photographs or a video recording, and, using image Editing software, compositing the photographs or the video frames into a seamless loop of sequential frames. This is done in such a way that motion in part of the subject between exposures (for example, a person's dangling leg) is perceived as a repeating or continued motion, in contrast with the stillness of the rest of the image.

More info - https://www.skillshare.com/classes/Creating-Cinema-graph-Using-Adobe-Photoshop/1999133204