<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
  <Grid.Triggers>
    <EventTrigger RoutedEvent="Grid.Loaded">
      <BeginStoryboard>
        <Storyboard TargetName="jim2" TargetProperty="Opacity">
          <DoubleAnimation From="1" To="0" Duration="0:0:4"
          AutoReverse="True" RepeatBehavior="Forever"/>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Grid.Triggers>
  <Image Name="jim1" Source="jim1.gif"/>
  <Image Name="jim2" Source="jim2.gif"/>
</Grid>