self.button.setIcon(self._icon)
self.button.setIconSize(QtCore.QSize(128, 128))
self.button.setMinimumSize(QtCore.QSize(128, 128))
self.button.setMaximumSize(QtCore.QSize(128, 128))
self.ui.PoseBtn_GridLayout.addWidget(self.button, 0, 0, 1, 1)
How to add widget to gridlayout starting from top-left corner