Image on Mobile looks crappy

Hi, I have a question. I have this page: https://emma-jewels.com/pages/over-mij/
And on desktop the picture looks amazing. But as soon as you go to mobile, first of all the image size is way to small i would love to have it somewhat bigger, but beside that I want to adjust the photo so you see the lady’s head instead of her neck. Can someone help me with this? Thanks in advance!!

The page I need help with: [log in to see the link]