We are occasionally asked why we used images instead of text in our math courses, both for quizzes and for media.
The use of images provided reliable, consistent reproduction of math characters across browsers and platforms at the time the course was produced (given the technologies supported at that time in the browsers).
The process used to render the images from the text sources was automated, and did not produce the clarity we would have preferred, but it was the best solution we could find at the time.
As technology continues to evolve, so do our processes and products. We always strive for the highest quality we can achieve, and your suggestions and feedback are always welcome.