当test.jpg大小超过Grid大小时就出现滚动条,请前辈指导上！先感谢了

<UserControl x:Class="LandQualityViewerApplication.AddIns.StatisticsResultWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:toolkit="http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit" 
    mc:Ignorable="d"
    d:DesignHeight="411" d:DesignWidth="780">
    <toolkit:BusyIndicator x:Name="StatisticsBusy">
        <Grid Width="748" Height="322" Name="reportGrid">
            <Grid.Background>
                <ImageBrush Stretch="None" ImageSource="/taizi.AddIns;component/Images/test.jpg"/>
            </Grid.Background>
            
           
        </Grid>
    </toolkit:BusyIndicator>
</UserControl>