You can show images in Silverlight using Image control.  You can furthermore bind Source property of the image to byte[] type property of a business object.  You would think this is sufficient, but it is not.  You will need a converter to convert byte array into image source.

Here is the class for converter

public class ImageSourceConverter : IValueConverter
{

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        BitmapImage bitmap = new BitmapImage();
        bitmap.SetSource(new MemoryStream((Byte[])value));
        return bitmap;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Here is how this class is used in a control:

<UserControl.Resources>
       <helpers:ImageConverter x:Key="ConvertImage"/>
   </UserControl.Resources>

<Image Source="{Binding Path=MyByteArrayPropertyName, Converter={StaticResource ConvertImage}}" />