1. Image reading
2. Image display
namedWindow(const String &winname, int flags = WINDOW_AUTOSIZE)
imshow(const String &winname, InputArray mat)
3. Image Saving
#include <opencv2/opencv.hpp> //the basic building blocks of the library
#include <iostream>
using namespace cv;
using namespace std;
int main()
{
Mat img, gray;
img = imread("pic_saved.jpg", IMREAD_COLOR);
namedWindow("img", WINDOW_NORMAL);
imshow("img", img);
imwrite("img.jpg", img);
waitKey(0);
return 0;
}