[wvxvw]

var xml:XML = <p>
<img src="images/float_head.jpg" width="100"/>
<IMG SRC="http://www.images.com/float_head.jpg"/>
</p>;
var re:RegExp = /(?<=src=")[^"]+(?=")/gi;
var htmlText:String = xml.toXMLString();
var srcs:Array = htmlText.match(re);
trace(srcs);
// images/float_head.jpg,http://www.images.com/float_head.jpg
// assume both are not valid
htmlText = htmlText.replace(new RegExp(srcs.join("|"), "gi"), "Symbol1");
var tf:TextField = new TextField();
tf.multiline = true;
tf.wordWrap = true;
tf.htmlText = htmlText;
tf.width = 200;
tf.height = 200;
addChild(tf);