Is your feature request related to a problem? Please describe.
Right now the ViewChild is called libEnterViewport, just because it is the default NgxIntersectionDirective we are using. But its up to the user if he maybe wants to use another directive, that loads (setImage) the image earlier or later. If he does, then the naming is not precise anymore.
Describe the solution you'd like
With the ViewChild we are passing the used directive (no matter which one is used in the template)to the component. So the preferred naming would be something like #intersectionDirective