Fit the size of the images on the homepage to the slider dimension – Minimatica

Good morning, I need a help for my website http://www.pugliò.it. I’m using minimatica theme, and if you go to my website homepage, you’ll see that the images which appear on the preview on the slider do not fit with the size of the slider (in practice, I want to delete the blacks spaces that are created in the top, bottom, or left and right of the image). i searched in the other topics, but I didn’t find a solution. How can solve this problem?
Thank you very much