How to set image on QPushButton ?

The size of the button will be correct, to reisze the icon  pixmap size:

QPixmap pixmap("image_path");
QIcon ButtonIcon(pixmap);
button->setIcon(ButtonIcon);
button->setIconSize(pixmap.rect().size());

Try this code:

QPushButton *button = new QPushButton;
button->setIcon(QIcon(":/icons/..."));
button->setIconSize(QSize(65, 65));

The given below code is simple:

QPixmap pixmap("image_path");
QIcon ButtonIcon(pixmap);
button->setIcon(ButtonIcon);
button->setIconSize(pixmap.rect().size());
button->setFixedSize(pixmap.rect().size());