HarmonyOS 如何将base64数据转换为图片

let that = new util.Base64Helper(); 
let base64 = 'iVBORw0KGgoAAAANSUhEUgAAAB4AAAAtCAMAAAxxxxxxxxaXE2QU03QE02QU48PEs0Q0s2QU42Qk43QE43QU03QU04P043QE43QVA3QU7fFG+6AAAADnRSTlMAu3fuESKPVd1mzESqM0jcJEgAAACOSURBVHjatZBJEsAgCARV3BP5/3Oj3mdIZZlrF9CMs+Jx2sSKE/7FIEMmxxxTuisS8aYRWTykA060xDtKipVelhLYiGRU+6WhJdHai1QK+6X6ZeFXYt9rBEOhzosCaqnfHPtO2TfpV0JXOxgXB/v5t7q0PZ1CN66I2+D3460q/lodkgpdjibeNm/fVtLk4YEK1O5uSkxxxxlFTkSuQmCC'; 
let result:Uint8Array = that.decodeSync(base64, util.Type.MIME); 
let buf:ArrayBuffer = result.buffer as ArrayBuffer 
const context: Context = getContext(this); 
const path1: string = context.cacheDir + "/pixel_map1168.jpg"; 
let file = fs.openSync(path1, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE); 
 
fs.write(file.fd, buf).then(async (writeLen) => { 
 
  console.info("write data to file succeed and size is:" + writeLen); 
  fs.closeSync(file); 
}).catch((err: BusinessError) => { 
  console.info("write data to file failed with error message: " + err.message + ", error code: " + err.code); 
}); 
 
})