Blog post images on index page getting stretched

Hello.

Recently I updated my wordpress to the latest release, as well as my jetpack. After doing so I realized my blog post images on my index page are getting stretched, and I am unable to figure out why this is happening.

I did not make any css or template changes to any of my pages before or after updating wordpress/jetpack.

The images should be showing as 325 x 250 ( resized from the images’ original size of 750 x 500 ) , but they are showing up as 325 x 500 on my index page, which is really unsightly. I trawled through my css and php files but I cannot for the life of me remember where the resize parameters are set, nor can I find it.

The images show up correctly as 750 x 500 pixels once they load on their single post pages.

Any help in fixing this is greatly appreciated ! Thank you so much !

The blog I need help with is halcyonrealms.com.

The page I need help with: [log in to see the link]