Yes you can, try registering event like:
myLoader.contentLoaderInfo.addEventListener(Event.COMPLETE,function(e:Event){
dispatchEvent(new CustomEvent(CustomEvent.COMPLETE, "<imageType>"));
}, false, 0, true);
And Add new Class, extending the Event class:
public class CustomEvent extends Event {
public static const COMPLETE:String = "CustomEventComplete";
public var imageType:String = "";
public function CustomEvent(type:String, imageType:String = "", bubbles:Boolean = false, cancelable:Boolean = false){
super(type, bubbles, cancelable);
this.imageType = imageType;
}
override public function clone():Event {
return new CustomEvent(type, customTarget, bubbles, cancelable);
}
}
Now you can register for CustomEvent.COMPLETE & get the image type in the listener.