I have an iPhone 6s and am running iOS 10. I just tried to take a photo using the earphones volume up and down but nothing triggered. I also tried another pair of earphone, but it still didn't work. Is there a setting I'm missing? or did they disable this in iOS 10.
I successfully took a photo via the following process with iPhone 7 & iOS 10 & the apple earbuds (with lightning connector, and also with lightning to 3.5mm jack variant of Earbuds):
Open the default iPhone camera app and, with earbuds connected, press volume down on the in-line remote.
However, the above process did not work when the apple earbuds were replaced by a set of Anker bluetooth earbuds, paired and connected to the phone.