.QCheckBox::indicator {
    width: 15px;
    height: 15px;
}

.QCheckBox::indicator[state="0"] {
    image:url(:/img/normal.png);
}

.QCheckBox::indicator[state="1"] {
    image:url(:/img/fail.png);
}

.QCheckBox::indicator[state="2"] {
    image:url(:/img/warning.png);
}

.QCheckBox::indicator[state="3"] {
    image:url(:/img/inital.png);
}