code: async function createThumbnails (target, images) {
    for (const x of images) {
      const imagePath = path.join(target, x)
      const thumbPath = path.join(target, `${x}.thumb.jpg`)
  
      try {
        // Background and flatten are for transparent PNGs/Gifs.
        // We force a white background here.
  
        await sharp(imagePath)
          .resize(450)
          .background({r: 255, g: 255, b: 255, alpha: 1})
          .flatten()
          .jpeg()
          .toFile(thumbPath)
      } catch (e) {
        const msg = chalk.dim(`(${e.message})`)
        console.warn(`The '${chalk.bold(x)}' thumbnail has not been generated. ${msg}`)
      }
    }
  }
docs: Create thumbnails. For each provided images, generate a low-res jpg thumbnail. Even for gif.  We don't check if the format of the images is valid, since the check is already done when constructing the images object.