ESPIED theme – potfolio photos downsizing

Trying to add photos to a portfolio post in the Espied theme.
Some are previewed full size and others are small. It’s driving me crazy!
All the photos are set up the same size in PS, I’ve tried fiddling with the code, and re-uploading.
Here’s a preview…

https://ericahartwick.wordpress.com/portfolio/ad-campaign/

The last photo…I think that speaks for itself.

Help pleasseee! Thanks