Utilise un QLabel et fais :


void ContactWidget::onPictureReceived(QtTapioca::ContactBase *contactBase ,QtTapioca::Avatar *avatar)
{
   if ( mPrivateContact != contactBase )
     return;
   QMimeData *mimeData = new QMimeData;
   mimeData->setData( avatar->mimeType() , avatar->data() );
 
   if (mimeData->hasImage()) {
        setPixmap( QPixmap::fromImage( qvariant_cast<QImage>(mimeData->imageData()) ) )
   }
 
}