Switch images to GraphQL for faster loading

[Frijol]

The images on the site are very slow to load in low-internet situations. In order to speed up page loading times while making our site more visually navigable, we should implement GraphQL and load images that way. (e.g. https://www.pluralsight.com/guides/how-to-set-up-graphql-in-a-react-app)

Minimum version of this is to implement for just #339