The difference between having images of something and having a knowledge of the same thing has been a subject of reflection for centuries, and some of the most important Greek tragedies focused on that point. A great part of infor-mation now consists of images: image has become the language of many people. Authors have already written on the necessity of learning how to read images. In this article the interest of learning how to write images will be experiment-ed in the context of Mathematics Teaching. Our experiments have taken place in the Electrical Engineering and Com-puter Science Department of the Institute of Technology of Valenciennes. Different kinds of students have been con-cerned aged from 15 until 25, in different circumstances: Festival of Science, Mathematics lectures or more specialized courses on Robotics and Vision. The experiments have been mainly used with low-cost material: free software like Py-thon, OpenCV and cheap hardware like Raspberry Pi are sufficient to obtain pretty good results.