Cropping and Resizing Issues

I'm having a bit of an issue with cropping. My impression of the croping and scaling was that if I set a size of 600x400, it will no matter what, spit out a 600x400 picture, even if it has to scale it up.

If I submit a 700x350 image, it ends up being something like 600x300, which breaks my template. Are there any other sizing and cropping options I'm missing? My code is below:

<div class="col-md-4 col-sm-4 featured-block"> <a href="our-staff.html" class="img-thumbnail"> <img src="<perch:content id="featuredImage" type="image" width="600" height="400" crop="true" label="Featured Image"/>" alt="<perch:content id="featuredAlt" type="text" label="Description"/>"> <strong><perch:content id="featuredTitle" type="text" label="Title"/></strong> <span class="more">read more</span> </a> </div>