tinplater wrote:
I believe the OP is laboring under the illusion that he needs to remove the images in the filmstrip BEFORE he adds new images for another show. All he needs to do is select images or folder from lightroom library, go to slideshow, and the old ones are gone, new ones there ready for editing, selecting, etc.
I'm of the impression he's working with LR CC (the web version, not Classic) and I am not familiar with that interface as I have not installed it.