Из Ассистанта:
void QSplashScreen::drawContents ( QPainter * painter ) [virtual protected]
Draw the contents of the splash screen using painter painter. The default implementation draws the message passed by showMessage(). Reimplement this function if you want to do your own drawing on the splash screen.
Пиксмапа на виджете:
QPainter painter( my_widget );
painter.drawPixmap( 123, 456, my_pixmap );