This plugin is a fancy image lazy loader. It scans all the content filtered
by the_content, and replaces the images with an embedded tiny thumbnail
(40px by proportional height). This is injected inline into the page and
a blur filter is applied to make it look nicer. As the user scrolls through
the page, once the blurry image comes into view, it is replaced by the
original image.
This plugin does quite a lot of file reading and processing, which can increase the TTFB. It is highly recommend that if this plugin is utilized, you use a WordPress cache plugin like Cache Enabler, so that the images are not being reprocessed every time a page is loaded.
This plugin is WebP aware! The server-side script checks to see if a .webp file exists for the original image, and if the browser is compatible, the front-end script will upgrade the original image to the webp version. This methodology is cache and CDN friendly!