It appears it is not snapshot.jpg, but rather snapshot-00000-2017-12-19_09-26-46.543.jpg.
The root challenge is there is no easy way to find out which snapshot was created via software; issue #18 is compounding that by eliminating the option to pipe.
No filename specified. Using snapshot.jpg
No device specified. Using <AVCaptureDALDevice: 0x7fe46e430940 [FaceTime HD Camera (Display)][0x4015000005ac1112]>
Capturing image from device "<AVCaptureDALDevice: 0x7fe46e430940 [FaceTime HD Camera (Display)][0x4015000005ac1112]>"...% [ .src/tmp/imagesnap ]
home % ls -l snapshot*.jpg
-rw-r--r-- 1 nick staff 163059 Dec 19 09:26 snapshot-00000-2017-12-19_09-26-46.543.jpg
[ .src/tmp/imagesnap ]
It appears it is not snapshot.jpg, but rather snapshot-00000-2017-12-19_09-26-46.543.jpg.
The root challenge is there is no easy way to find out which snapshot was created via software; issue #18 is compounding that by eliminating the option to pipe.