<Button HorizontalAlignment="Left" Margin="20,22,0,0" Name="button1" Width="136" Height="142" VerticalAlignment="Top" Click="button1_Click">
            <Button.Template>
                <ControlTemplate>
                    <Image x:Name="Imginbtn" Source=".\Images\wpf.jpg" Tag=".\Images\wpf.jpg" Stretch="Fill" ImageFailed="Image_ImageFailed" Height="142" Width="136" />
                </ControlTemplate>
            </Button.Template>
        </Button>
        <Button Height="142" Width="136" Margin="184,22,240,0" Name="button2" VerticalAlignment="Top" Click="button2_Click">
            <Image Source=".\Images\a.jpg" Stretch="Fill"/>
           
        </Button>   如何申明变量。要在另一window中使用这个图。