Use
_sanitizer.bypassSecurityTrustUrl to tell angular src value is safe
You can change your code like below.
Import DomSanitizer
import { DomSanitizer } from '@angular/platform-browser';
Inject this dependency in to the contructor
constructor(private domSanitizer: DomSanitizer) { }
myReader.onloadend = (e) => {
this.base64Image = domSanitizer.bypassSecurityTrustUrl(myReader.result);
console.log(this.base64Image);
}