[mayakwd]

я вам уже всё расписал и так.
ну вот вам код, правда он ни чем вам не поможет, полагаю.

private var userToCheck : VKUser;
private var avatarURLCheckTimer : Interval;
 
private function startChecking () : void {
   avatarURLCheckTimer = Interval.setInterval (getUserAvatarInfo, 5000);
   avatarURLCheckTimer.start();
}
 
private function getUserAvatarInfo() : void {
  var call : NetworkCall = vkAPI.post (new GetProfiles([vkUser.uid], [GetProfiles.PHOTO_MEDIUM]);
  call.addEventListener(NetworkEvent.COMPLETE, getAvatarCompleteHandler);
}
 
private function getAvatarCompleteHandler(event : NetworkEvent) : void {
  if (event.success) {
    var data : ArrayData = event.data as ArrayData;
    var checkingUserData : VKUser = data.value[0] as VKUser;
    if (checkingUserData.photoMedium != vkUser.photoMedium) {
       dispatchEvent(new AvatarCheckEvent(AvatarCheckEvent.CHANGE, checkingUserData.photoMedium));
    }
  }
}