We shouldn't remove one of images
At first, The cover image is not repeated inside slideshow in many cases like this:
Also in current page their caption and URL and dimensions are completely different:
Thus I shouldn't remove one of them because at least we'll lost one of the original captions in IV and in some cases like this we'll lost one of the images because there is no rule for repeating images.
My template displays the original objects in the IV nicely and completely.
Kindly find a real problem and don't make new rules for your own.
Good luck