I've just added an dedicated package for v4l2grab utility, built from the latest sources and providing more options (like saving in jpeg instead of the ppm format) than the version included into the v4l-utils package.
That's a nice small utility akin' to fswebcam, but even simpler, allowing you to quickly capture an image from the attached webcam.
More details at
https://github.com/twam/v4l2grab
or
v4l2grab – Grabbing JPEGs from V4L2 devices
If you have v4l-utils package installed on your board, you will get the below error message, just use "opkg install --force-overwrite v4l2grab" to get past it.
root@edison1:~# opkg install /tmp/v4l2grab_20141109-r0_core2-32.ipk
Installing v4l2grab (20141109-r0) to root...
Collected errors:
* check_data_file_clashes: Package v4l2grab wants to install file /usr/bin/v4l2grab
But that file is already provided by package * v4l-utils
* opkg_install_cmd: Cannot install package v4l2grab.