This is a conceptual question. In my particular case, I am using slick.js to create an image carousel for a website. Since these are high resolution photographs, I want to speed up the page load time by allowing the photographs to be loaded asynchronously instead of on page load.
When looking through the documentation for this library, I saw the settings available for the 'lazyLoad' property with little information as to what those settings mean in practice.
Essentially my question is, what is the difference between progressive and on-demand in the context of lazy loading.