Edit Summary Block images to look like Image Block: Poster

I am trying to make the Summary Block thumbnail images on my client's site appear more like Image Block: Poster. Essentially they want to use the functions of the Summary Block for posts, but for the summary block to have the Title, Excerpt, and button on top of the images. Example attached.

Is there a way to do this with CSS?

Hi. Can you share link to page where you added summary block? We can give the code to achieve this effect easier