Whilst random decorative images can add to the students’ cognitive load and are not recommended, relevant graphics have been shown to improve learner engagement with materials.

Zygomatic produces several tools that are all incredibly simple to use, useful, free, and online:
Typography Editor – Create your own designs with backgrounds (or upload your own), badges, borders, rulers, frames, corners, and other ornaments; add text in a variety of fonts with backdrops and shadows. For PC or mobile interface. Image can be saved or shared.
Toony Tool – Create your own cartoons. You can also upload your own images and characters. Very easy to use, drop and drag.
Online chart – Create a variety of charts – all downloadable.