Images Slider Problem

Hello,
I tried to added image slider by option “Cover”, becuse I wanted a full screen image, but couldn’t get clear images, the image was in shade and very big, 50% of picture was cut down, I couldn’t see the whole image.
By option ‘Contain”, could get clear images, but not in full screen.
How did you make the clear image slider on the home page-Shop?

Thanks.
Regards.
Lily