10uF is a common value for capacitance, 16uF would be extremely odd, especially on PC parts, so definitely 10uF.
The reason it's 16V is simply because 10uF 16V are commonly available. The card manufacturer stocks up on a huge supply of those and can use them almost anywhere, even if they wanted to use some on a 12V line.
As Postman mentioned, the location in the photo is probably on 3.3V for the power to the nearby RAM. Even though that location doesn't need a 16V rating, when the caps are that small, the cost has pretty much bottomed out. There's no money saved by stocking a version with a lower voltage spec than that.
If you are considering replacement with a lower voltage rating and want to confirm the voltages each cap will see, just check it with a meter.