common.js uses the data: uri in the browser, but this is not supported by IE7 (and earlier).
var data = new Image();
data.onload = data.onerror = function(){
if(this.width != 1 || this.height != 1)
... // data: uri not supported
else
... // data: uri is supported
}
data.src = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///ywAAAAAAQABAAACAUwAOw==";
(In [4987]) refs #1841 - exportImage and outputImage are now deprecated (since OFC has been replaced); will be removed if/when PiwikMap.swf switches to non-Flash