I tried this and get the following error message: 

Sorry, you are not allowed to access this document. Only users with the following access level are currently allowed to do that:

- Human Resources/Employee

- Administration/Access Rights

(Document model: res.groups)

Thank you for helping. But, your answer is 8 years late. From the time I was evaluating Odoo 😁

From the odoo website click on your login name on the top right hand corner and select My account.  Then from the odoo backend select your name again and then Preferences.  On the top right of the pop-up window you will see where you can add your image.  Hover over the picture and select the pencil.