Homepage feature image slider issue

Hello, I originally had a maximum of 34 images on my homepage. Last night I wanted to update the order of the post associated with the feature image and also reduce it down to 25 images. When I made the update, the system automatically changed the image to 4 images. I tried updating the number of images and it could only let me go up to 20. I am not sure what happened. I am hoping to have 25 images, is it possible or is it currently locked at 20? If I knew I wouldn't have touched it... Here is my website. Thank you!