You can appreciate Monet's Woman with a Parasol in person through your own unaided vision. But perhaps you need eyeglasses. If you use eyeglasses while looking at the painting in the National Gallery, you're still appreciating Monet's painting. The same would be true if there were a window opposite the painting, and you were sitting in a tree and observing the painting through binoculars. Further, surely it makes no difference how the binoculars work. Ordinary binoculars work by rearranging light through lenses as it streams from the object to the eye. Digital binoculars, on the other hand, work by having sensors transform the light from the object and then creating images on tiny screens inside. When you look at Woman with a Parasol through digital binoculars, what you're appreciating is the painting through the binoculars, not the two tiny images on screens inside the binoculars.
But notice that with digital binoculars, you can do two things. You can look at the little screens inside or you can, as it were, look through them. The intentional objects are different: if you look at the screens, you see the screens; if you look through the screens, you see the world (including Woman with a Parasol, if that's where you're pointing the binoculars). When you look at the screens, your attention is at least in part on the pixels, the quality of the color rendition, the glare, and so on. When you look through the screens, your attention is on something out there in the world. The two experiences have distinctly different phenomenal feels, and you can go back and forth between them as in the case of the two duck-rabbit.
One more step. In Terry Pratchett's Discworld novels, instead of cameras they have iconographs, which is a box with an imp that paints quickly with a little paintbrush. We can imagine binoculars made on that principle. A pair of eagle-eyed imps very quickly paint two little pictures in the box, constantly updating them. You could look through imp-binoculars at Woman with a Parasol, but we could also look at the pictures in the box, admiring the imps' workmanship. You could switch back and forth just by redirecting your attention. Note, however, that both ways of using the imp-binoculars could involve skill and knowledge. It might be that when you first look into the imp-binoculars, it's obvious to you that there are paintings inside (maybe you can see the brush strokes and the texture of the canvas) and only with experience do you learn to correlate the images in the imp-binoculars with the external world. On the other hand, if your visual acuity is not as good or if the imps are really good, you might not realize that there are paintings inside--it might feel like just looking through a pair of holes in a wall, and only with experience do you learn to see the images as little paintings.
At this point, it should be clear that one can look at a painting through its reproduction. It's just a matter of directing your attention and intentionality appropriately. It does, however, take knowledge. You need to know that the painting is a reproduction, just as you need to know that the imp-binoculars track the world to see the world through them.
This gives us an account of the properly aesthetic harm done by the forger of a particular painting (the forger of a particular painter's style is a more complicated case, but perhaps can be handled similarly). By blocking the viewer from knowing that the reproduction is a reproduction, the forger prevents the viewer from seeing the original through the forgery. It is the forgery rather than the original that is seen, but it is misconstrued. On the other hand, if the forger honestly informed us that this was a reproduction, she would be doing us a service--she would be providing us with a telescope pointed at the original.
What is interesting about this account of the properly aesthetic harms done by a forger is that it does not require us to value the viewing of an original over the viewing of a perfect reproduction. In fact, this account of what is bad about forgery depends precisely on the value of reproductions. One could--though one need not--hold that viewing Woman With a Parasol naked-eye, through eyeglasses, through optical binoculars, through digital binoculars, through imp-binoculars and through a reproduction are all equally valuable when the image quality is equal. In fact, viewing through a reproduction could be even more valuable, for instance if one's eyesight is poor and the reproduction is larger in size than the original. But it is important that we see the original through the reproduction, that the reproduction be a window on the artist's production, and indirectly on the artist's soul.
Likewise, we should see God through the world and especially through our neighbor.