Simple window with mouse scrolling (PyQt5) (based on https://gist.github.com/acbetter/e7d0c600fdc0865f4b0ee05a17b858f2)

mouseScroll.py

import sys
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *

import sys
import traceback

def exception_hook(exctype, value, a):
   a = traceback.format_exception(exctype, value, a)
   print("".join(a))
sys.excepthook = exception_hook

class HelloWindow(QMainWindow):
   def __init__(self):
      QMainWindow.__init__(self)

      self.setMinimumSize(QSize(200, 200))

      centralWidget = QWidget(self)
      self.setCentralWidget(centralWidget)

      gridLayout = QGridLayout(self)
      centralWidget.setLayout(gridLayout)

      self.label = QLabel("Hello World from PyQt", self)
      self.label.setPixmap(QPixmap("test.png"))

      self.scroller = QScrollArea()
      self.scroller.setWidget(self.label)
      self.scroller.setCursor(Qt.CrossCursor)
      gridLayout.addWidget(self.scroller, 0, 0)

      self.scroller.mouseMoveEvent = self.mouseMoveEventLeft
      self.scroller.mousePressEvent = self.mousePressEventLeft
      self.scroller.mouseReleaseEvent = self.mouseReleaseEventLeft

   def mousePressEventLeft(self, event):
      self.label.setCursor(Qt.ClosedHandCursor)
      self.initialPosX = self.scroller.horizontalScrollBar().value() + event.pos().x()
      self.initialPosY = self.scroller.verticalScrollBar().value() + event.pos().y()

   def mouseReleaseEventLeft(self, event):
      self.label.setCursor(Qt.OpenHandCursor)

   def mouseMoveEventLeft(self, event):
      self.scroller.horizontalScrollBar().setValue(self.initialPosX - event.pos().x())
      self.scroller.verticalScrollBar().setValue(self.initialPosY - event.pos().y())

app = QtWidgets.QApplication(sys.argv)
mainWin = HelloWindow()
mainWin.show()
sys.exit( app.exec_() )