Something

function InsertImage(img, width, align)
{

	var theIframe = document.getElementById("EditorWidgIframe");
	var theSelection = "";

	if (theIframe.contentWindow.document.selection)
	{
		theSelection = theIframe.contentWindow.document.selection.createRange().text;
	}
	else
	{
		theSelection = theIframe.contentWindow.getSelection();
	}

	if(align != "center")
	{
		document.getElementById("EditorWidgIframe").contentWindow.document.getElementById("iframeBody").innerHTML  += "<img src=\"" + img + "\" style=\"width: " + width + "px; float: " + align + "; padding: 4px;\" alt=\"\" />";
	}
	else
	{
		document.getElementById("EditorWidgIframe").contentWindow.document.getElementById("iframeBody").innerHTML  += "<div style=\"text-align: center;\"><img src=\"" + img + "\" style=\"width: " + width + "px; padding: 4px;\" alt=\"\" /></div>";
	}
}