How to make custom callback in keras to generate sample image in VAE training? I'm training a simple VAE model on 64*64 images and I would like to see the images generated after every epoch or every couple batches to see the progress.

when I train the model I wait until the training is done and then I look at the results.

I tried to make a custom callback function in Keras that generates an image and saves it but couldn't do it. is it even possible? I couldn't find anything like it.

it would be awesome if you refer me to a source that explains how to do so or show me an example
I think the two following links could help you 1, 2.  

The first one is a tutorial, which introduces you how to display images in TensorBoard.
If you look at the part on the confusion matrix, you should find a way to make your desired callback, i.e. a callback which involves displaying an image.  

The second link is also a tutorial that shows you how to write your very own custom callback in TensorFlow with Keras.  

I think by combining both tutorial you should have a pretty good idea how to do what you want.