angular 6 default image if not found code example
Example: if image is broken show alternative image angular
<img class="thumbnail-image" src="{{user.profile_image}}" onerror="this.src='assets/images/user.jpg'" alt="alternative" />
<img class="thumbnail-image" src="{{user.profile_image}}" onerror="this.src='assets/images/user.jpg'" alt="alternative" />