title: How set default image?
body: <p>DataGrid:</p>
  
  <pre><code>&lt;sdk:DataGridTemplateColumn&gt;
                          &lt;sdk:DataGridTemplateColumn.CellTemplate&gt;
                              &lt;DataTemplate&gt;
                                  &lt;Image Tag="{Binding photo}" MinWidth="50"  Source="{Binding photo, Converter={StaticResource ConvertNullImageKey}}"/&gt;
                              &lt;/DataTemplate&gt;
                          &lt;/sdk:DataGridTemplateColumn.CellTemplate&gt;
                      &lt;/sdk:DataGridTemplateColumn&gt;
  </code></pre>
  
  <p>Converter if value not uri return iamge from ImageResource.noimage. But this bitmap...How return URI on bitmap?</p>
  
  <pre><code>public class ConvertNullImage : IValueConverter
          {
              public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
              {
                  try
                  {
                      Uri uri = new Uri(value.ToString(), UriKind.Relative);
                      return uri;
                  }
                  catch { return new Uri(ImageResource.noimage); }
              }
  
              public object ConvertBack(object value, Type targetType, object parameter,
                                        CultureInfo culture)
              {
                  throw new NotImplementedException();
              }
          }
  </code></pre>