How to display featured posts area images as landscape images instead of cropped

Hello, I just found Temptation and I rather enjoy its simplicity. I’m experimenting with the Featured Posts Area. I notice that if a featured image does not exist for a post, the placeholder image is displayed at 215×135 pixels, even though the image itself is 542×340 pixels. However, if a featured image is set on a page, the image is displayed at 230×340 pixels, which is cropped from 542×340 pixels.

Is there a setting that I’m missing, where images will be scaled instead of cropped?

Thanks!