Add image with text displaying only on hover

Any idea of the simplest way to add an image with text displaying only on hover , and there’s a darkening of the image on hover- like seen on this site Yellowstone - Portfolio. Preferably done with Gutenberg blocks or if not than simple code or a lightweight plugin.
thank!

There might be a block for that, I don’t know, but if I were coding it with existing blocks, I’d put the text as a caption, and use CSS to style the caption.