CMS photo size issue

Having trouble with image sizes in the “Projects” template. I’m looking to make the Thumbnail and main image the same dimensions without distorting.

Currently the thumbnail is shrunk just a little and the main image gets stretched wide.

Should i keep all images a certain size (I’m keeping a general 1200 x 800) and set the image/div to a certain setting?

I just want them to look the same as both thumbnail and main image at the width i’ve set.

Should i change the image sizes to something like 1280 x 720?

Here is my public share link: 1

Website: 1

Thanks in advance.