HarmonyOS 鸿蒙Next图片压缩后文件大小反而变大了

HarmonyOS 鸿蒙Next图片压缩后文件大小反而变大了 当使用ImagePacker进行图片质量压缩的时候，如果将原图直接压缩为100%质量，文件大小反而会变大，是什么原因？

console.log(">>>begin compress:" + uri)
const startTime = new Date().getTime()
const file = await fs.open(uri, fs.OpenMode.READ_ONLY)
const stat = await fs.stat(file.fd)
const fileSize = stat.size
console.log(`>>>original size:${fileSize} Bytes`)
const source = image.createImageSource(file.fd)
const packer = image.createImagePacker()
const packerOpt: image.PackingOption = {
  format: "image/jpeg",
  quality: 100
}

const helper = photoAccessHelper.getPhotoAccessHelper(context)
const asset = await helper.createAsset(photoAccessHelper.PhotoType.IMAGE, "jpg")
const tmpFile = await fs.open(asset, fs.OpenMode.CREATE | fs.OpenMode.READ_WRITE)
const packingResult = await packer.packing(source, packerOpt)
await fs.write(tmpFile.fd, packingResult)
// await packer.packToFile(source, tmpFile.fd, packerOpt)
const tmpStat = await fs.stat(tmpFile.fd)
const tmpFileSize = tmpStat.size
console.log(`>>>result size:${tmpFileSize} Bytes`)
await fs.close(tmpFile.fd)