Testing “WP Retina 2X” Plugin For WordPress

Now that WordPress 4.4 is out (and used on this site as of December 8, 2015) I wanted to test the Retina 2X plugin for WordPress to see how it works and if it makes a difference on my 4K monitor and iPhone.  I exported two images from Lightroom, one is 1024 pixels wide, the other 3840 pixels wide (4K).

1024 pixels version below.  The blog displays images here at 818 pixels wide, and if you click you get the large version. 

The 3840 pixel version.  The theory is that high resolution displays should show a higher quality version than the one above (which is limited by the file size).