Interesting. Most mobile ad networks (including ours at Adfonic) choose image size based on the user agent of the device. Your screenshot is 480x800, so I assume that's your native resolution. MMA 6:1 banners come in four standard sizes: 120x20, 168x28, 216x36, and 300x50. As you say, this one seems to be 252x42, and it's been sloppily upsized from 168x28. That is pretty egregious, but it means both the Guardian and the ad network are at fault. 1) The ad network should at least be serving the 300x50 version. True, a quandary in mobile advertising at the moment is that there is no standard 6:1 banner size above this size. The standards simply aren't keeping up with the rapid evolution in device resolution, so a growing number of high-end devices are missing out. 2) As you say, the Guardian shouldn't be resizing the image -- clearly this is being done in the template. And yeah, the ad isn't actionable.. that's just dumb.