Yes, changing your logo is a simple process. First, click on the blue "Edit Photo" link where indicated below.
Next, hover your mouse over your existing logo. The box will appear gray and you will see the word "Remove" in the upper right hand corner. Click the "Remove" box.
Once you have removed your existing logo, you will notice that it is gone from both the menu bar and the logo upload field.
Click in the logo upload field and select your new logo that you would like to add. Once you have added it, click on the blue "Save Info" button.
Once your new logo is saved, it will now be visible in the menu bar as well. That's it!