Gatsby +Sanity: Darkmode image that allow alternate image (Sanity Schema Code)

DarkModeImages.js

/** @jsx jsx */
import { jsx, useColorMode } from "theme-ui"
import { buildImageObj } from '../../lib/helpers'
import { imageUrlFor } from '../../lib/image-url'

function DarkModeImage (props) {
  const [colorMode] = useColorMode()  
  const SanityImageToggle = (colorMode == 'light') ? props.primaryImage : props.darkmodeImage
  return (
    <figure>
    <img src={imageUrlFor(buildImageObj(SanityImageToggle)).url()} alt={props.alt}/>
    </figure>
  )
}

export default DarkModeImage