You can use yourself's. Just take it at home, choose the best one, print it out on the photo paper, and cut it. I did. I also did for my hubby. Both worked out pretty good. :-) Or you can take an ugly one in Walgreen, Fedex, ... If you need to "楼下去付钱再照", it could be a line there.
I went there on Friday morning around 9am, there's long line in front of the building already, but after I retake the picture and done with everything it's only 10:30am, BUT the line in front of the building was much longer!! so go there early!!