I am using the Featured Image Slider on the front page of my website. The problem I have is as follows:
Under “Slider Options”, I have increased the number of slides to “10” and saved this change. But under “Featured Image Slider Options”, it still only allows me to upload 4 images at most.
What do I do to increase the number of slider images?
You are doing correct. Go to slider options and change the default value 4 to 10. Then you have to refresh customizer. After refreshing the customizer then only you will be able to upload more slides.