Keras Tensorboard callback does not write images

I am trying to visualize the scales of my Keras model using Tensorboard. Here is the model I'm using:

model = Sequential([
    Conv2D(filters=32, kernel_size=(3,3), padding="same", activation='relu', input_shape=(40,40,3)),
    MaxPooling2D(pool_size=(2, 2)),
    Conv2D(filters=64, kernel_size=(5,5), padding="same", activation='relu'),
    MaxPooling2D(pool_size=(2, 2)),
    Flatten(),
    Dense(1024, activation='relu'),
    Dropout(0.5),
    Dense(43, activation='softmax'),
])
model.compile(optimizer='sgd',
              loss='categorical_crossentropy',
              metrics=['accuracy'])

      

        
        
        
      

    

and I train with this call:

model.fit_generator(
    ...
    callbacks = [
        ModelCheckpoint('models/gtsrb1-{epoch}.hdf5', verbose=1, save_best_only = True),
        TensorBoard(log_dir='tblogs/', write_graph=True, write_grads=True, write_images=True),
        EarlyStopping(patience=5, verbose=1),
    ],)

      

        
        
        
      

    

However, when I run TensorBoard, this is what I get:

Scalar and graphics look fine, so it's not the wrong problem logdir

. What am I doing wrong here?