Update Example to use ImageEx to show something for files with no images

SampleTest/MainPage.xaml

@@ -58,8 +58,9 @@
                                     <ItemsControl.ItemTemplate>
                                         <DataTemplate x:DataType="graph:DriveItem">
                                             <StackPanel>
-                                                <Image DataContext="{x:Bind RemoteItem, Converter={StaticResource OneDriveThumbnailConverter}}"
-                                                       Source="{Binding Result.Medium.Url}" Width="176" Height="176"/>
+                                                <controls:ImageEx DataContext="{x:Bind RemoteItem, Converter={StaticResource OneDriveThumbnailConverter}}"
+                                                                  PlaceholderSource="/Assets/FileIcon.png"
+                                                                  Source="{Binding Result.Medium.Url}" Width="176" Height="176"/>
                                                 <TextBlock Text="{Binding Name}"/>
                                                 <TextBlock Text="{Binding Size, Converter={StaticResource FileSizeConverter}}"/>
                                             </StackPanel>

SampleTest/SampleTest.csproj

@@ -130,6 +130,7 @@
     </AppxManifest>
   </ItemGroup>
   <ItemGroup>
+    <Content Include="Assets\FileIcon.png" />
     <Content Include="Properties\Default.rd.xml" />
     <Content Include="Assets\LockScreenLogo.scale-200.png" />
     <Content Include="Assets\SplashScreen.scale-200.png" />