In fact, you can't change the avatar to your own in your mobile app - only to the standard ones that are already there. You can change the avatar through your poker client on your computer. It's pretty simple: click on the avatar icon and select "edit image" and then select "upload new image".

Desktop client: To make a deposit, login to your account and click the 'Cashier' button. Next, click on the 'Stars Transfer' button and follow the on-screen instructions. App users: To make a deposit, login to your account, select the Real Money tab in the lobby, then tap on the 'Deposit' button.