How to display a little image near a QSlider

[Lykurg]

Hi the size of the widget change when the value of the label change from 1 to 2 digits ( for example from 9 to 10 ) and from 2 to 3 digits ( for example from 99 to 100 ) and viceversa.

Yes and therefore use QWidget::setFixedSize() for the label with a proper size that there is enough space for 3 digits. Then the label wont resize ==> the frame/layout neither.