http://www.markrafferty.com/wp-content/w3tc/min/7415c412.e68ae1.css
Line 11:
.postItem img {
height: auto;
width: 450px;
}
You can either edit your CSS, or you can listen to Mageek and use INLINE STYLING to override the CSS styling that's happening:
<img src="theSource" style="width:30px;" />
Avoid setting both width and height, as the image itself might not be scaled proportionally. But you can set the dimensions to whatever you want, as per Mageek's example.