I would love it if someone could show me how they add the water below images. I have a great many awesome cemetery pics as well as memorial pics, and angels, that I would love to be able to add here, but would like to know the secret to having that realistic feature on the images.

I would love it if someone could show me how they add the water below images. I have a great many awesome cemetery pics as well as memorial pics, and angels, that I would love to be able to add here, but would like to know the secret to having that realistic feature on the images.