<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
	<mx:Script>
		<![CDATA[
			[Embed(source="sample.png")]
			private var Sample1:Class;
			[Embed(source="sample2.png")]
			private var Sample2:Class;
			[Bindable]
			private var imageSource:Class;

			private function changeImage(event:Event):void {
				// このイベントのターゲットはRadioButtonGroup
				var target:RadioButtonGroup = RadioButtonGroup(event.target);
				// RadioButtonGroupのselectedValueは選択したRadioButtonのvalueが入ってる
				// valueはObject型なのでintにキャスト
				var selected:int = int(target.selectedValue);
				if (selected == 1) {
					imageSource = Sample1;
				} else {
					imageSource = Sample2;
				}
			}
		]]>
	</mx:Script>
	<mx:HBox>
		<mx:RadioButtonGroup id="imageGroup" change="changeImage(event);"/>
		<mx:RadioButton groupName="imageGroup" label="画像1" value="1"/>
		<mx:RadioButton groupName="imageGroup" label="画像2" value="2"/>
	</mx:HBox>
	<mx:Image source="{imageSource}"/>
</mx:Application>