Not able to get index of items in gridview

xaml code

<GridView  x:Name="GetImages"SelectionChanged="GetImages" ItemsSource="{Binding}" HorizontalAlignment="Center" SelectionMode="Multiple">

.........<DataTemplate>

<StackPanel>
<Image Source="{Binding Path=Image}"/>
</StackPanel>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>

Things need to be done:

1.  need to bind images to Gridview
2.  let user select multiple items and should have some selection effect
3.  get the index/image paths of selected items and transfer them to another page

Problems: 

• cannot get the index of selected items as the SelectionMode is"Multiple"
  
• Only return the first index of the selected items