bookmark bar icon size. By default, none is selected, but you can make the icons
either small, medium or large. Again, you can change this setting by going to
File --> Preferences --> User Preferences. In the "Display Options" section of
the Basics tab you will see a place to change the bookmark icon size. Test out
the different sizes to see what you like.
In order for the changes you've made to take effect, you'll need to restart