ui->listChat->setStyleSheet("background-image: url(res/sdlogo.png) ;background-attachment: fixed ;background-position: center center ;background-repeat: no-repeat;background-size: cover");
}else{ui->listChat->setStyleSheet("background-image: url(res/sdlogo2.png) ;background-attachment: fixed ;background-position: center center ;background-repeat: no-repeat;background-size: cover");}