Retina.js is an open source script that makes it easy to serve high-resolution images to devices with retina displays.
http://retinajs.com/
JavaScript Libraries and Functions · Media
Get access to data on 1,822,735 websites that are Retina JS Customers. We know of 701,057 live websites using Retina JS and an additional 1,121,678 sites that used Retina JS historically and 345,464 websites in the United States.
Get a list of 1,822,735 websites using Retina JS which includes location information, hosting data, contact details, 1,027,566 currently live websites which includes 326,509 domains that redirect to sites in the list. 1,121,678 sites that used this technology previously and 345,464 websites in the United States currently using Retina JS.