QTextDocument and background-images

Hi,
I copy the code from the tutorial:

Tutorial

It works's fine, but the background Image doesn't show.
Why does the <img> picture shown but the <span id='bgimage'>not ????

Is there an trick?

Here an short example:

Code:

#include <QApplication>
#include <QTextDocument>
#include <QTextBrowser>
#include <QVariant>
#include <QDebug>
 
int main(int argc, char *argv[])
{
     // Q_INIT_RESOURCE(application);
      QApplication app(argc, argv);
 
QString html;
html = "<html><head>"
       "<link rel='stylesheet' type='text/css' href='format.css'>"
       "</head><body>"
       "Your HTML code with tags, which have classes or ids. For example "
       "<span class='red'>this text is colored red</span>.<br/>"
       "And you can also display images: <img src='myImage.jpg'><br/>"
       "Combine css and images: <span id='bgimage'>foo bar</span>"
       "</body></html>";
 
// Your CSS code
QString css;
css  = "span.red { color:#DE0000; } "
       "span#bgimage { background-image: url('myImage.jpg');} ";
 
// Crate a QTextDocument with the defined HTML, CSS and the images
QTextDocument *doc = new QTextDocument;
 
/*
 * This shows how to bind the images, where the name for QUrl is the same name
 * which you use in your HTML and CSS. In QPixmap just use the normal syntax of
 * the Qt resource system.
 */
doc->addResource( QTextDocument::ImageResource, QUrl( "myImage.jpg" ), QPixmap( ":myImage" ) );
doc->addResource( QTextDocument::ImageResource, QUrl( "bg.png" ), QPixmap( ":bg" ) );
 
/*
 * And now bind the css, which you have defined in the QString css.
 */
doc->addResource( QTextDocument::StyleSheetResource, QUrl( "format.css" ), css );
doc->setHtml( html ); // binds the HTML to the QTextDocument
 
/*
 * This QTextDocument can now set to any QTextBrowser.
 */
QTextBrowser *tb = new QTextBrowser( 0 );
tb->setDocument( doc );
tb->show();
 
 
      return app.exec();
}