Как вставить изображение в tableWidget по нажатию на кнопку?

QTableWidget::setCellWidget(int row, int column, QWidget *widget)

Задает отображение данного виджета в ячейке в заданной строке и столбце, передавая право владения виджетом таблице.

QTableWidget::setItem(int row, int column, QTableWidgetItem *item)

Устанавливает элемент для данной строки и столбца в item. Таблица становится владельцем элемента.

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


class Ui_MainWindow_BookAdmin(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(660, 469)
        MainWindow.setStyleSheet("QGroupBox{\n"
"    min-width:  640px;\n"
"    max-width: 640px;\n"
"    min-height: 419px;\n"
"    max-height: 419px;\n"
"}\n"
"")
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.groupBox = QtWidgets.QGroupBox(self.centralwidget)
        self.groupBox.setGeometry(QtCore.QRect(9, 9, 642, 421))
        self.groupBox.setObjectName("groupBox")
        self.gridLayout = QtWidgets.QGridLayout(self.groupBox)
        self.gridLayout.setObjectName("gridLayout")
        self.gridLayout_5 = QtWidgets.QGridLayout()
        self.gridLayout_5.setObjectName("gridLayout_5")
        
        self.tableWidget = QtWidgets.QTableWidget(self.groupBox)
        self.tableWidget.setObjectName("tableWidget")
        self.tableWidget.setColumnCount(6)
        self.tableWidget.setRowCount(4)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(0, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(0, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(1, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(2, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(3, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(4, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(5, item)
        self.gridLayout_5.addWidget(self.tableWidget, 0, 0, 1, 1)
        
        self.gridLayout.addLayout(self.gridLayout_5, 0, 0, 1, 1)
        self.gridLayout_2 = QtWidgets.QGridLayout()
        self.gridLayout_2.setObjectName("gridLayout_2")
        self.pushButton_2 = QtWidgets.QPushButton(self.groupBox)
        self.pushButton_2.setObjectName("pushButton_2")
        self.gridLayout_2.addWidget(self.pushButton_2, 0, 1, 1, 1)
        self.pushButton = QtWidgets.QPushButton(self.groupBox)
        self.pushButton.setObjectName("pushButton")
        self.gridLayout_2.addWidget(self.pushButton, 0, 0, 1, 1)
        self.pushButton_3 = QtWidgets.QPushButton(self.groupBox)
        self.pushButton_3.setObjectName("pushButton_3")
        self.gridLayout_2.addWidget(self.pushButton_3, 1, 0, 1, 2)
        self.gridLayout.addLayout(self.gridLayout_2, 1, 0, 1, 1)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 660, 21))
        self.menubar.setObjectName("menubar")
        self.menu = QtWidgets.QMenu(self.menubar)
        self.menu.setObjectName("menu")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.action = QtWidgets.QAction(MainWindow)
        self.action.setObjectName("action")
        self.action_3 = QtWidgets.QAction(MainWindow)
        self.action_3.setObjectName("action_3")
        self.menu.addAction(self.action)
        self.menu.addSeparator()
        self.menu.addAction(self.action_3)
        self.menubar.addAction(self.menu.menuAction())

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.groupBox.setTitle(_translate("MainWindow", "Варианты номеров"))
        
        item = self.tableWidget.verticalHeaderItem(0)
        item.setText(_translate("MainWindow", "__"))
        
        item = self.tableWidget.horizontalHeaderItem(0)
        item.setText(_translate("MainWindow", "Изображение"))
        item = self.tableWidget.horizontalHeaderItem(1)
        item.setText(_translate("MainWindow", "Адрес"))
        item = self.tableWidget.horizontalHeaderItem(2)
        item.setText(_translate("MainWindow", "Кол-во мест"))
        item = self.tableWidget.horizontalHeaderItem(3)
        item.setText(_translate("MainWindow", "Цена за ночь"))
        item = self.tableWidget.horizontalHeaderItem(4)
        item.setText(_translate("MainWindow", "Свобод. места"))
        item = self.tableWidget.horizontalHeaderItem(5)
        item.setText(_translate("MainWindow", "Оценка"))
        self.pushButton_2.setText(_translate("MainWindow", "Добавить обьявление"))
        self.pushButton.setText(_translate("MainWindow", "Удалить обьявление"))
        self.pushButton_3.setText(_translate("MainWindow", "Сохранить изменения"))
        self.menu.setTitle(_translate("MainWindow", "Главное"))
        self.action.setText(_translate("MainWindow", "Профиль администратора"))
        self.action_3.setText(_translate("MainWindow", "Выйти"))


class IconDelegate(QStyledItemDelegate):
    def initStyleOption(self, option, index):
        super(IconDelegate, self).initStyleOption(option, index)
        option.decorationSize = option.rect.size()        


class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow_BookAdmin):
    def __init__(self):
        super().__init__()
        self.setupUi(self)
        
        self.tableWidget.verticalHeader().setDefaultSectionSize(70)
        self.tableWidget.horizontalHeader().setDefaultSectionSize(100)

        rows = self.tableWidget.rowCount()
        for row in range(rows):
            
            button = QPushButton('Загрузить \nкартинку', self)
            self.tableWidget.setCellWidget(row, 0, button)
            button.clicked.connect(
                lambda ch, row=row, btn=button: self.button_pushed(row, btn)
            )

        delegate = IconDelegate(self.tableWidget)
        self.tableWidget.setItemDelegateForColumn(0, delegate)
            
    def button_pushed(self, row, btn):    
        filter_file = "Images (*.png *.jpeg .jpg)"
        get_photo, ok = QFileDialog().getOpenFileName(
            self, 
            'Select Images', 
            '', 
            filter_file
        )       
        if not get_photo:
            return

        btn.hide()
        item = QTableWidgetItem(QIcon(get_photo), "")
        self.tableWidget.setItem(row, 0, item)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())