Add stock photograph(s) in place of gray area

[redshiftzero]

@nmorduch suggested we replace the gray area on the site with a nice stock photograph:

We probably want something involving police officers/cars/etc that is neutral.

Note that there are several pages with this gray area, and we could have a different photograph for each page.

[nmorduch]

I generally recommend Stocksy. The photos cost money, but not a huge amount, and they're a cooperative.

Here's a search for police car photos. They also have short videos if you want to be fancy for the front page, but I wouldn't bother. Especially because loading videos is mildly rude and more trouble than it's worth imo, even though it's cool.

There's also Adobe Stock, which can be a cheaper option. Here's a search for police car photos there.

[redshiftzero]

Nice links - these looks pretty good and are impartial in nature:

https://www.stocksy.com/365739 https://stock.adobe.com/images/nypd-cars/112602?prev_url=detail https://stock.adobe.com/images/a-police-car-rushes-to-the-emergency-call-with-lights-turned-on/95525264?prev_url=detail