So, how do we cycle background images when the very images we're using depend on our current resolution and orientation? That pretty much rules out cycling out a single image. Instead, we're going to have to swap out entire style sheets. Here we go:

<link rel="stylesheet" href="rotating0.css" id="rotatingBackgrounds" />

It's a pretty simple style sheet to begin with, but you could make it as complex as you like. We're not accounting for HD display versus SD displays for now. The iPhone 4 with Retina display (326 ppi) was released in June 2010. Ever since, the trend is moving toward HD screens anyway, so I'm simply assuming most people have updated their smartphone within the last two years and that they either have a high resolution screen or very soon will. Keep in mind also, that we are on the edge of the LTE (fourth generation mobile broadband) ubiquity. Someday soon, mobile speeds will rival home broadband speeds.

Now, is this really an excuse for laziness...