New GraphQL node (ChildImageSharp) from another node that may or may not be an image url string

[dungle-scrubs]

I'm using Gatsby v3 with gatsby-source-shopify and have exposed some metafields. Currently those metafield are queried through GraphQL like this:

query MyQuery {
  allShopifyProduct {
    nodes {
      metafields {
        namespace
        key
        value
      }
    }
  }
}

The above works great and I can access the metafields. However, if one is a string containing an image url, I can't run it through ChildImageSharp from the frontend.

The value field can contain a string, number, or boolean. What I'm trying to achieve is, when it's a string and also an image url, I'd like to either create a new GraphQL node (or extend the current one?) to be able to query the image using ChildImageSharp. In my mind, the structure would look like this:

query MyQuery {
  allShopifyProduct {
    nodes {
      metafields {
        key
        namespace
        value {
          value // Would be null if value is a valid image url string, else it would be a string, boolean, or number
          image { // Would be null if the value is not a string that has been validated as an image url
            localFile {
              childImageSharp {
                fluid {
                  srcSet
                }
              }
            }
          }
        } 
      }
    }
  }
}

The direction I'm heading isn't working and I'm not sure how to approach it, but this is what I'm thinking so far:

// gatsby-node.js
exports.onCreateNode = ({ node, actions, createNodeId }, options) => {

  // If it's not a metafield, return early
  if (node.internal.type !== 'ShopifyProductMetafield') {
    return
  }

  const { createNodeField } = actions
  let isImage = false
  isImageURL(node.value).then((is_image) => {
    isImage = is_image
  })

  createNodeField({
    node,
    name: 'image',
    value: isImage ? node.value : null,
  })

}

I'm stuck at this point. Am I taking the wrong approach?