Angular5中基本授权的安全图像

我有一个基本授权的图像网址,我需要动态加载图像.授权后,图像将作为数据返回.如何使用授权处理此图像.目前我尝试这样

<img [src]=" getImage(res.imageurl) | async" />



  getImage(imageUrl: String): Observable<File> {
   let headers = new httpHeaders();
headers = headers.append("Authorization","Basic " + btoa(this.domain + '/' + logindata.username + ':' + logindata.password));
    return this.http
        .get(imageUrl,{headers:headers},{ responseType: ResponseContentType.blob })
        .map((res: ResponsE) => res.blob());
}

@Component({
    template: `
        <img [src]="img.src + '?bearer=' + bearToken"/>
    `
})
export class FooComponent {
    img = {
        src: 'https://angular.io/assets/images/logos/angular/logo-nav@2x.png'
    }
    bearerToken  = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...';
}