The GetDesignTimeValue method is a helper method used by the ImageField class to determine what value to display for a field when rendering an ImageField object in a designer. If real data cannot be retrieved from the data source at design time, the value returned by this method is displayed instead.
Notes to Inheritors
When extending the ImageField class, you can override this method to return a different value to display for the field in a designer.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)