sudo apt-get install libopencv-dev python-opencv

g++ -ggdb `pkg-config --cflags opencv` -o `basename opencvtest.cpp .cpp` opencvtest.cpp `pkg-config --libs opencv`

#include <opencv2/highgui/highgui.hpp>
using namespace cv;
 
int main()
{
    Mat img = imread("/home/alfred/Desktop/screen.jpg",CV_LOAD_IMAGE_COLOR);
    imshow("opencvtest",img);
    waitKey(0);
    return 0;
 }