Customize Woo Commerce Product Slider

Hello, I have a shop and the slider need fixing, currently the first image is not showing in the thumbnail below, and the thumbnail doesn't crop the image causing the whole slider structure looks bad when the wrong image ratio is uploaded, I haven't tried uploading many image for i.e 15 to see how the thumbnail looks like, and if that not structured correctly I would like to fix that as well, and I also would like for all this works for video too.