Public Property ImageFormat As ArcGISDynamicMapServiceLayer.RestImageFormat

public ArcGISDynamicMapServiceLayer.RestImageFormat ImageFormat {get; set;}

<esri:Map Background="White" HorizontalAlignment="Left" Margin="5,5,5,5" Name="Map1" 
             VerticalAlignment="Top" Height="200" Width="400" BorderThickness="5" BorderBrush="#FF30EBEB">
            
       <!-- Set the ImageFormat to JPG. The default value for the service is PNG24. -->
       <esri:ArcGISDynamicMapServiceLayer 
             Url="http://sampleserver1.arcgisonline.com:80/arcgis/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer" 
             ImageFormat="JPG" />
             
   </esri:Map>

private void ArcGISDynamicMapServiceLayer_Initialized(object sender, System.EventArgs e)
{
    // The myArcGISDynamicMapServiceLayer (an ArcGISDynamicServiceLayer object) and TextBlock_ImageFormat
    // (a TextBlock object) were defined previously in the XAML or code-behind.
                 
    // Get the first layer in the LayerInfo collection. 
    ArcGISDynamicMapServiceLayer myArcGISDynamicMapServiceLayer = (ArcGISDynamicMapServiceLayer)Map1.Layers[0];
    
    // ImageFormat (Read/Write).
    
    // Set the .ImageFormat to JPG. The default value for the service is PNG24.
    myArcGISDynamicMapServiceLayer.ImageFormat = ArcGISDynamicMapServiceLayer.RestImageFormat.JPG;
    
    // Get the .ImageFormat property.
    TextBlock_ImageFormat.Text = myArcGISDynamicMapServiceLayer.ImageFormat.ToString();
}

Private Sub ArcGISDynamicMapServiceLayer_Initialized(ByVal sender As System.Object, ByVal e As System.EventArgs)
    ' The myArcGISDynamicMapServiceLayer (an ArcGISDynamicServiceLayer object) and TextBlock_ImageFormat
    ' (a TextBlock object) were defined previously in the XAML or code-behind.
    
    ' Get the first layer in the LayerInfo collection. 
    Dim myArcGISDynamicMapServiceLayer As ArcGISDynamicMapServiceLayer = Map1.Layers.Item(0)
    
    ' ImageFormat (Read/Write).
    
    ' Set the .ImageFormat to JPG. The default value for the service is PNG24.
    myArcGISDynamicMapServiceLayer.ImageFormat = ArcGISDynamicMapServiceLayer.RestImageFormat.JPG
    
    ' Get the .ImageFormat property.
    TextBlock_ImageFormat.Text = myArcGISDynamicMapServiceLayer.ImageFormat.ToString
End Sub