Changing and adjusting the photo size in the mega menu- Symmetry theme

Hi,

I would like to change the image size in the mega menu and I am wondering how I can do it. Could you please help me?

I would like to adjust the width and height as in the photo below and move it to the right, so that the photo is displayed without any margins. DROLL store is mine and this is what it looks like now.

Theme: Symmetry

Thank you in advance
Tomek