Fixed core dumped on close

imagecontroller.py

@@ -42,6 +42,7 @@ class ImagePreloader(QThread):
     def __init__(self):
         """Initializes the preloader thread."""
         super().__init__()
+        self.setObjectName("ImagePreloaderThread")
         self.path = None
         self.index = -1
         self.mutex = QMutex()