UPDATE: 1.7RC5 was released on 19 Feb 2013. These instructions will work for RC4 and RC5.
So you have installed OSTicket v1.7rc4 and now you want to customize it a little by replacing the logo images on the staff login, staff side, and pdf printing. Then this is the article for you. There are two ways to achieve this goal. The easiest way is for those not familiar with CSS, or those not comfortable with modifying the template css files.