title: ImageSourceConverter error for Source=null
body: <p>I'm binding the Source property of an Image to a string. This string may be null in which case I just don't want to display an Image. However, I'm getting the following in my Debug output:</p>
  
  <blockquote>
    <p>System.Windows.Data Error: 23 : Cannot
    convert '&lt;null&gt;' from type '&lt;null&gt;' to
    type
    'System.Windows.Media.ImageSource' for
    'en-AU' culture with default
    conversions; consider using Converter
    property of Binding.
    NotSupportedException:'System.NotSupportedException:
    ImageSourceConverter cannot convert
    from (null).    at
    System.ComponentModel.TypeConverter.GetConvertFromException(Object
    value)    at
    System.Windows.Media.ImageSourceConverter.ConvertFrom(ITypeDescriptorContext
    context, CultureInfo culture, Object
    value)    at
    MS.Internal.Data.DefaultValueConverter.ConvertHelper(Object
    o, Type destinationType,
    DependencyObject targetElement,
    CultureInfo culture, Boolean
    isForward)'</p>
  </blockquote>
  
  <p>I'd prefer if this wasn't displayed as it's just noise - is there any way to suppress it?</p>