Images stretching and distorting

I have purchased the commercial use package for Huge IT Portfolio Gallery. I am using the Gallery/Content-Popup template. I see that you have provided ways to size thumbnails and images. However, there does not seem to be a way to render the images at the actual size they are. There also does not appear to be a way to constrain proportions. As a graphic designer, It looks rather unprofessional having my portfolio images stretched.

http://www.alisonricedesign.com/category/portfolio/

Thanks you.

https://wordpress.org/plugins/portfolio-gallery/