A/B testing is an iterative test method to verify and improve the effectiveness of an advertising campaign or website performance by testing different variations (A or B). The purpose is to retain only the variations that gives the best results. This method was initially used for mailing campaigns. However, it can be extended to advertisements inserted on other sites, banners, or even the sites themselves. The principle is always to present several variants to a large number of Internet users, and see which among those will trigger more or less page views.

To feel good a web site should be fast. Now, pictures slow down the rendering of the site. You should therefore tweak the images you display so that your site does not become too slow. To achieve this we can adjust several variables: the picture resolution, the color sampling and the picture format. Using wisely all three at once saves plenty of space and speed.