class_docstr: Represents one of the three thumbnails at the top of the window.
code: def __init__(self, parent, index, name):
      super().__init__()
  
      self.parent = parent
      self.index = index
  
      layout = QtWidgets.QVBoxLayout()
  
      label = QtWidgets.QLabel(name)
      label.setAlignment(
          QtCore.Qt.AlignmentFlag.AlignHCenter
          | QtCore.Qt.AlignmentFlag.AlignVCenter
      )
      layout.addWidget(label, 0)
  
      self.image = QtWidgets.QLabel()
      self.image.setAlignment(
          QtCore.Qt.AlignmentFlag.AlignHCenter
          | QtCore.Qt.AlignmentFlag.AlignVCenter
      )
      self.image.setMinimumSize(800 // 3, 600 // 3)
      layout.addWidget(self.image)
      self.setLayout(layout)
  
imports: import os
  from pathlib import Path
  import shutil
  import sys
  from matplotlib.backends.qt_compat import QtCore, QtGui, QtWidgets
  from matplotlib.backends.qt_compat import _exec
label_desc: Use image node_id 1 to create a new Thumbnail object from inherited base classes: QtWidgets with example: obj = Thumbnail(parent, index, name)