Could you just mention which part of doc I have to read

because the aim is to use the system provided by QWizard like this:

Wizards consist of a sequence of QWizardPages. At any time, only one page is shown. A page has the following attributes:
A title.
A subTitle.
A set of pixmaps, which may or may not be honored, depending on the wizard's style:
WatermarkPixmap (used by ClassicStyle and ModernStyle)
BannerPixmap (used by ModernStyle)
LogoPixmap (used by ClassicStyle and ModernStyle)
BackgroundPixmap (used by MacStyle)

using this is very simple ; my question is just to know how to resize the wizard when you set the bannerPixmap

If there is no simple way ; I will design a Widget in Qt designer and set it on the top for all QWizardPages

David