graphql.js

export const pageQuery = graphql`
  query($slug: String) {
    allWordpressPost(sort: {order: ASC, fields: date}) {
      edges {
        node {
          featured_media {
            localFile {
              childImageSharp {
                fluid(sizes: "(min-width: 1280px) 327px, (min-width: 768px) 39vw, 81vw") {
                  src
                  // [...]
                }
              }
            }
          }
        }
      }
    }
  }
`