Which php file is this logo image in??

In the top left corner is the logo image

thesloeruin.com

But for the life of my I can’t figure out which php file it is kept in because I added it using Appearance>Customise.

Reason I need to find it is because as you can see it sticks out a bit from the nav bar..

Also what would be the best way to fix that? I was going to just make it the same height as the nav bar but maybe there is a better way..