Square photos on homepage are different sizes

I just changed to Market Theme today and really like it. However, I added a new post today and on the homepage when my featured image appears as the Square Photo, it is a smaller square than all of the other photos on the page. Is there a reason for this or can this be updated?

Here is a link to my site, Christina Cappuccino. The image with the article on “Repurpose for a Purpose” is the image that is smaller than all of the other images.

I would greatly appreciate any help or feedback on this!

-Christina