I couldn’t figure out how to edit the php file to resize the featured image, so I cropped the image instead. If you know the image size, you can use Picasa to resize the image first. In Picasa, double click the image, and then select crop. From the drop-down, select Add Custom Aspect Ratio, enter the size of the image, and click OK. Then you can click the crop type you want, and slide it over the photo with your mouse. Once you have it cropped properly, click Apply. Then just export the image, maintaining the original size. Upload to WordPress and set as the featured image, and it should be sized appropriately.
