Uncheck to preserve old behaviors data URI printed on the page server-side. Check to enable Blur client-side. <br><b>Pros:</b> Client-side doesn't add ugly data URI to the page till required, and automatically cleared when done, meaning lighter page weight at initial and end, and at the next pages if any stored data found (meaning cacheable unlike server-side), but not during runtime animation. It leverages lazy load mechanism. <br><b>Cons:</b> Client-side does a HTTP request initially. Can use localStorage option below to cache them.