How do I snap a photo on my iPhone with the apple earphones
I successfully took a photo via the following process with iPhone 7 &amp; iOS 10 &amp; 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.