Web developers have been working on the problem of sending different files to different devices for a few years, and a number of solutions have been proposed. Out of the plethora of methods out there, I'm going to look at one which uses inbuilt WordPress functionality. This method uses WordPress-featured images combined with a plugin called mobble to identify mobile devices.
However, before we start it's important to address one assumption about mobile connections.
It's easy to assume that mobile users will be on a slower connection than desktop users, but this may not always be the case. Consider the growing number of smartphone owners who use them to access the Internet at home.
Note
A survey of smartphone users (http://blog.compete.com/2010/03/12/smartphone-owners-a-ready-and-willing-audience) found that 84 percent of them use their phone to access the Internet at home, making this the most...