Logo settings can be found under (design > theme editor):
Choose 'logo'

Upload your favicon (icon of your tab) here.
Recommended: 48x48, 96x96, 144x144, 192x192, 240x240 pixels.

Upload your logo here.
Recommended: 185x53 pixels.

Position of the logo
Select the position of your logo here. The logo can be placed to the left or in the middle.
The search bar also moves depending on your choice of position.