how to convert html response of type image/png in angular

getBase64ImageFromURL(url: string) {   return Observable.create((observer: Observer<string>) => {     // create an image object     let img = new Image();     img.crossOrigin = 'Anonymous';     img.src = url;     if (!img.complete) {         // This will call another method that will create image from url         img.onload = () => {         observer.next(this.getBase64Image(img));         observer.complete();       };       img.onerror = (err) => {          observer.error(err);       };     } else {         observer.next(this.getBase64Image(img));         observer.complete();     }   });}