How do I change the blog post image hover effect?

Hello, when I am on the blog page and hover over a featured image, it gets darker and has a large plus sign in the middle, which when clicked links to the larger version of the image.

How can I change this effect? I want to modify it to look like the blog demo video from Highend, where you can see arrows on the side to scroll through the blog images, or to just change the image itself as I see fit. There is no customization option in the blog section of the theme settings that I can find.

Thanks for your help.