Learning computer programming for students of the age of 14-18 is difficult and requires endurance and engagement. Being familiar with the syntax of a computer language and writing programs in it are challenges for youngsters, not to mention that understanding algorithms is also a big challenge. To help students in the learning process, teachers need to increase their engagement and motivation by giving them interesting and entertaining tasks. Implementing different image processing algoritms can be very efficient for enhancing their programming skills, since by running their programs on real pictures taken by cameras, they can examine the effects of these programs. This article carefully selects and introduces image processing algorithms that are based on basic computer algorithms and are understandable for secondary school students. It also shows how to apply them in programming classes and how to provide the discovery learning for students.