Javascript:
var imgHTML = "<img " +
"src='http://i.msdn.microsoft.com/fp123580.AppHome2(en-us,MSDN.10).png'"
+ " alt ='apps for Office image' img/>";
function setHTMLImage(imgHTML)
{
Office.context.document.setSelectedDataAsync(
imgHTML, { coercionType: "html" },
function (asyncResult) {
if (asyncResult.status == "failed") {
write('Error: ' + asyncResult.error.message);
}
});
}