Hi HoaLT. Wonderful news! The code you provided worked!
Apparently because of my being such a Squarespace novice and my ignorance, I didn't know that my home page photo was a 'gallery image', and not a 'cover image'. Someone from Squarespace customer care examined my site and pointed that out to me. So I followed your initial instructions and added the code... and it worked! No more white space beneath my Home page photo!
You are a GENIUS! But what matters even more than being a genius is being kind-hearted and having a willingness to come to the aid of others. I'm 68 years old, and having had no income for almost two years due to Covid restrictions, I'm doing everything that I can to get my career as an independent photographer back on track. Which is why I created a Squarespace website, and I just want everything to look as polished and professional as possible.
I can not possibly thank you enough. I wish you blessings and hope that others you encounter in life will be as kind to you as you have been to me. Thank you again and again.