Removing image

My website is at http://www.incentivesthinktank.org/.

I’m working with the Food and Diet theme at http://wordpress.org/themes/food-and-diet. This is a wonderful theme!

How can I remove the image (with the banana in the circles to the left of the word FoodDiet) in the upper left corner of the page? I’ve never edited a theme before, but if someone told me which piece of code to delete, I could probably press Ctrl + F, find the piece of code, and delete it. Is the piece of code I need to delete in the header.php template?

Thank you.