require 'magickcam' capture = Webcam.new image = capture.grab image.save 'new_image.jpg' capture.close
There is no need to instantiate an object from the Magickcam class if all you want is to capture a webcam image. The Magickcam gem includes the latest code from the rb_webcam source code on GitHub whereas the rb_webcam gem (as of 1-Dec-2012) still does not.
You will need to install imagemagick, and opencv. Here's what I installed
apt-get install imagemagick libcv2.3 libcv-dev libopencv-highgui2.3 libopencv-highgui-dev