Fix broken images in Quiet Card examples

[lazd]

Expected Behavior

No broken images

Actual Behavior

So many broken images

Steps to Reproduce

1. Go here http://opensource.adobe.com/spectrum-css/2.6.0/docs/?color=light&scale=medium&method=standalone#card---gallery
2. Be sad at broken images

Spectrum-CSS version

2.6.0

[GarthDB]

Fixed by #15