how to add an image to plotband

[Shawn Quinn]

Looks like they're using some internal methods of the Highcharts library in order to achieve that effect. You could do the same via custom JS (or GWT JSNI). Essentially, for every point in the series they're calling a custom JS function that does the following to create those images:

chart.renderer.image(
    'http://fil.nrk.no/yr/grafikk/vindpiler/32/vindpil.'+ windSpeed +'.'+ windDirection +'.png',
    point.plotX + chart.plotLeft - 15,
    240,
    30,
    30
)
.attr({
    zIndex: 5
})
.add();

That "image()" method simply creates a new "image" DOM element with the given attributes via jQuery (or whatever DOM wrapper is installed), and then the "add()" method adds it to the DOM.

Hope that helps,

 -Shawn