It's a bonafide phenomenon!
I'm talking about the idea of image hosting services that allow you to manipulate the URL to the image in order to transform it. So if you know you need multiple copies of an image in order to do the responsive images syntax justice, you don't have to actually make the images yourself, you just adjust the URL so that you have the perfect image for the job.
This idea of manipulating the URL has made its way into tons of image hosting services. Let's take advantage of what those services have to offer and do something above and beyond typical responsive images: let's art direct them.