What I'd like to do is load "normal" images on my site if a visitor is, for instance, on a monitor constrained device like a smartphone. But if they're on a big monitor with high DPI I'd like to load a high-res equivalent image. Preferably from the server-side or some way that doesn't require an extra step at load time so images still load as quickly as possible.
There are some questions about how to detect retina/high DPI devices using javascript: What is the best way to detect retina support on a device using JavaScript? or on the server: detect retina (HD) display on the server side but I want to apply that info to load the appropriate image client side.
