Visual Composer Post Grid Element

Hi,
I’m trying to overwrite the image in Post Grid element. In the post grid settings > image tab, I choose “custom” image cropping. When I set width and height to 200px it makes the images larger. It seems like the only way to make the images smaller is to reduce the size of the column, which I don’t want to do.
see it here: http://casa.hummingbirdwebdesign.com/ scroll to bottom of page.

Thanks,
Nancy