HarmonyOS Image如何显示base64的图片？

const base64String = `*****************`  
  
@Preview  
@Entry  
@Component  
struct ImageBase64 {  
  @State imagestr: string = ''  
  base64Image() {  
    let begin = 'data:image/jpeg;base64,'  
    return begin + base64String  
  }  
  aboutToAppear(): void {  
    this.imagestr = this.base64Image()  
  }  
  
  build() {  
    Row() {  
      Column() {  
        Image(this.imagestr)  
          .width(300)  
          .height(100)  
          .backgroundColor(Color.Green)  
      }  
      .width('100%')  
    }  
    .height('100%')  
  }  
}