...
tensorflow.python.framework.errors_impl.InvalidArgumentError: Matrix size-incompatible: In[0]: [28,28], In[1]: [784,128]
     [[{{node dense/MatMul}}]] [Op:__inference_keras_scratch_graph_2593]

yourimage = cv2.imread("yourimage.png", 0)

predicted_value = np.argmax(model.predict(yourimage))