Align pictures to center of page. Please help

Hi everyone. Currently stuck on the portfolio challenge. Here’s the link:

Anyone know how I can make the 3 pictures in the ‘portfolio’ section align to the center of page? Plus make those images separate from each other? I’ve tried everything, including adjusting column width, making the form into a grid etc. etc.

Really appreciate the help!

check this out.

Thank you very much!