Lotus Theme image dimensions

There isn’t a lot of support for this theme - and no option to add woocommerce - but its OK to use for a porfolio site - I just need to edit the shape of the images when they are displayed on the portfolio index page and underneath the portfolio item in the Related Projects list. I’m showing Quad posters which are 40x30 inch - The theme is cropping the top and bottom from the reduced image size because its not tall enough image holder.
I’m pretty new and not a coder - is this characteristic of the theme written in the jquery somewhere - I don’t think its just a CSS edit? Can I change it or do I have to start with a new theme!!!
Any help much appreciated…