That's in interesting one! I don't really know!
The logic of the screenshots is this:
- Launch Chrome
- Open a new 600x500 tab with JavaScript disabled
- Wait for the "domcontentloaded" flag to be set
- Wait 3 seconds to hopefully load all images etc
- Take a screenshot
- Close Chrome
It looks like if you disable JavaScript you get about 90% of the way there; your background image is also very big, so its possible that its not loading within the 3 second window.
I don't know that there's much I can do to fix that side of things; when your trying to automate screenshots on 2000 sites things just go wrong on some of them, particularity when they are media heavy

The SurfClub is due a redesign soon though and maybe we should add the option to set your own image as an alternative to the screenshot.
EDIt: Oh and as for the styling on your tab around the screenshot; it looks for background-image, background-color and color tags on the body; set those and it'll import them