Preloader is an image or a simple Gif which appears on the screen when you open a website while the rest of the page content is still loading.
This feature used to be embedded in Jupiter but it has been removed from Jupiter X.
This is the reason why we have removed Preloader from Jupiter X:
Preloader is a deprecated trend so we will never add it to Jupiter theme. It had an infamous starring with flash sites because the site was taking minutes to load.
Nowadays sites need to load almost instantly. Jupiter X is lighter, faster and more reliable than Jupiter. We take the performance of Jupiter X to the next level so that you won’t need to add a Preloader to your website again.