How Do I đăng tải an user icon?

As many of bạn obviously know I don't have an user icon. On my thông tin các nhân It says that I can "Upload A Photo" So on the Internet I found a cute bức ảnh of Cleo,Rikki, and Bella. And I copied and pasted. So I put it into my "Browse File" and I submited it but it didn't do anything. I tried this many times and still nothing happened. Please EXPLAIN how I can đăng tải an user icon.
Thanks,
retysumjohn