This example uses gridsome-source-sanity

Configuration

It is recommended to set schemaType to 'Image' if your Sanity studio does not contain any images in order to ensure that the targetField gets the type Image rather than Images.

gridsome.config.js 
module.exports = {
  siteName: 'Gridsome',
  plugins: [
    {
      use: 'gridsome-source-sanity',
      options: {
        projectId: '<project_id>',
        dataset: 'production',
        graphqlTag: 'default'
      }
    }
    {
      use: '@noxify/gridsome-plugin-remote-image',
      options: {
        'cache': false,
        'typeName': 'SanityImageAsset',
        'sourceField': 'url',
        'targetField': 'localFile',
        'targetPath': 'src/assets/sanity/remoteImage',
        'schemaType': 'Image'
      }
    }
  ]
}

GraphQL Query

{
  allSanityImageAsset {
    edges {
      node {
        url
        localFile
      }
    }
  }
}

GraphQL Result

{
  "data": {
    "allSanityImageAsset": {
      "edges": [
        {
          "node": {
            "url": "<sanity-remote-url>",
            "localFile": {
              "type": "file",
              "mimeType": "image/jpeg",
              //... and all other image properties
            }
          }
        }
        //...
      ]
    }
  }
}