What should be in the alt attribute where there is figcaption?

The same thing as in figcaption, and not empty because of the next question. But would the screen reader read it twice??

Can I use empty alt attribute?

Only use alt="" when the image should be hidden from screen readers. Empty alt is better than no alt attribute, because you are deliberate about it beiing empty.

What to write into alt text?

Emotion matters