Thumbnails/Images not cooperating with Windows Phone App Studio

So I'm trying out Windows Phone App Studio (app creator by Microsoft where you don't need to know any coding and to be honest, I'm surprised how much you can do with it). I brought my RSS feed in, but only the blog posts that don't have excerpts have working thumbnails/images for their post.

So the posts with excerpts show up like this: http://d.pr/i/6aag

I can modify how it grabs the image, and I've tried a few other options but still no luck. The original image source it uses is "{Data.ImageUrl} as seen here: http://d.pr/i/BoYh

Any help finding out what to put instead of "ImageUrl" would be appreciated!

For reference, heres my RSS feed: http://vibrampowered.com/?format=rss