Take a picture from terminal

There is another application which can be used to capture the images from the webcam named as Fswebcam. you can install that with

sudo apt-get install fswebcam

you can have a sample shot with the following command.

fswebcam -r 640x480 --jpeg 85 -D 1 web-cam-shot.jpg

In the above code syntax , -r stands for Image resolution , --jpeg stand for format type of the image & 85 for its quality standard, -D stands for delay set before capture.

Now your image finally saved with web-cam-shot.jpg name.

Hope that helps.

If you're looking for something automated webcam is pretty decent. It has lots of lovely options for pushing the photos over the Internet.

If you want something more manual, and we're talking about a camera supported by V4L/UVC (most of them) you can use streamer to capture a frame from the device:

streamer -f jpeg -o image.jpeg

Using avconv or ffmpeg, you can capture a frame from your device as well. For example:

avconv -f video4linux2 -s 640x480 -i /dev/video0 -ss 0:0:2 -frames 1 /tmp/out.jpg

or

ffmpeg -f video4linux2 -s 640x480 -i /dev/video0 -ss 0:0:2 -frames 1 /tmp/out.jpg

This will open /dev/video0 as a video4linux2 compatible device, set up resolution to 640x480, stream for 2 seconds (00:00:02 or simply 2), then capture one single frame, saving it to /tmp/out.jpg.

Check if your device is /dev/video0, as it can be different for you.

The available resolutions depend on your webcam. Mine goes up to 640x480 and I checked it with a tool called qv4l2, which is used to configure a video4linux2 device.

The -ss parameter is used to allow the device to start up correctly. Here in my tests, there is a fade-in effect while the camera is being turned on, so, if I just omit -ss 2, the captured frame will be very dark.