Greetings, Trent
Easier to help if we can have a link to the site, so we can examine & diagnose. Otherwise, I'm forced to guess.
Best guess-- the heights of the images that are not rescaling are being specified somewhere (in your HTML? CSS? both?) and that's preventing the browser from recalculating the height based on the flexible width. Just to reiterate, that's an educated guess based on what you've described. I could easily be wrong.
Have you tried using the support forum for the theme's authors?