Shopify Collection Page edits

We current have an option on our theme to show product images on Hover. This is great, but we would like to limit to just Images 1 and 2 (in order) where image 1 is the featured image, and 2 shows on hover. When the mouse moves off of the image it goes back to image 1.
We would then like to look at some buttons that preselect the filter (app) we have. I can provide examples, but basically main sizes and products.