For security reasons, it is not a good practice to download the file automatically without user consent or interaction. The download_button is perfect for this. Let the user press that button.
It is not necessary to save the image file to a disk. Just use fig bytes data into the download_button.
I agree. What if I have more than one image (a set of png chart image I have generated on a batch) to download? Can I somehow find a way to download them as separate files, but with one single down_load button βpressβ by the user.