Inherited description: This parameter provides the default XMLNAME for the class. If it is
empty then the class name will be used to construct a default XML name.
The default XMLNAME is used as the top level tag
when exporting objects and the export context
did not provide an XML container name.
Specifies the source of the image.
If the src attribute begins with an exclamation point, it is interpreted
as an XPath expression just as in the field attribute of the <item> tag.
This allows you to dynamically generate URLs within the XML data, and then
use these customized URLs as the image source. Note: when using ! to dynamically
get the image URL, it must be an absolute URL or it will not appear in the PDF