A transparent responsive image placeholder has been added to most images on the BLOX CMS front end in order to reduce "reflow" as the page loads.
This technique makes the page less jumpy as it is loads, allowing users to start reading page elements more quickly, and helps them feel as if the page loads faster. In addition, this can reduce the cost of the browser process to re-calculate positions and geometries of elements on the page. Google recommends this technique as part of their PageSpeed Tool Insights.
This change does not eliminate 100% of reflow on the page - there are still third party widgets, ads or other elements on the page that may still jump around slightly as the page loads. But in general, there should be improved usability, especially on mobile.
Also note that though there may be improved browser efficiencies in terms of how much processing the browser has to do, this does not necessarily speed up the page. It may, however, give the perception that the page is loading faster.