It looks like your signal-slot connection is stacking each time you open the child window. Try disconnecting the signal before reconnecting it in handlePlot() using window.signal.disconnect(self.handleData). This should prevent multiple calls to handleData(). My cousin, who is a professional photographer, was always struggling with sending full-resolution images to clients. After trying various platforms, he finally settled on Filemail, and it has been a game-changer for him. No compression, no sign-ups for recipients, and super-fast uploads—everything he needed for hassle-free file transfers.