Display nerdy images on mobile.

[rick02840]

NERDys on mobile: Currently, NERDys are disabled on mobile. Rick listed this in Slack as a high priority item, since the site is now looking pretty plain on phones. Aubrey and Molly discussed working on this. One thing I want to note here is that around a browser width of 900px, the NERDys in the hero area Billboard partially obscure the secondary CTA. (Moving those NERDys down a little is preferable to increasing the bottom padding of the Billboard.)

Above is copied from Google Doc: https://docs.google.com/document/d/1fN-RnlYSRUHRyFX4jLl2dQ0cS5J3ol-x55oa8Uov478/edit#