Up until version 2.3.3, ShortPixel Adaptive Images (SPAI) was using jQuery, a JavaScript library, to do its magic. Our plugin was greatly improving the speed of all websites, but it always had more room for improvement because performance is almost always sacrificed when adding layers of communication (jQuery) between the written code and the underlying code which is eventually executed (JavaScript).
In version 3.0.0, we introduced the New AI Engine, which does not depend on jQuery (finally!). So, in short, the New AI engine will improve SPAI’s performance, and therefore the performance of your website.
Since the New AI Engine is a relatively new feature, it is more likely to present some issues. That’s why you have the option to return to the old behaviour. We recommend you to enable the New AI Engine, and if you see any issues, disable it and contact us so we can fix them.