reading multiple images

edit

You can always load the images one by one manually:

//Assuming that the images live on the same directory where you executed your  OpenCV program
cv::Mat image_0 = cv::imread("0.jpg");
cv::Mat image_1 = cv::imread("1.jpg");
cv::Mat image_2 = cv::imread("2.jpg");
cv::Mat image_3 = cv::imread("3.jpg");
cv::Mat image_4 = cv::imread("4.jpg");
cv::Mat image_5 = cv::imread("5.jpg");
cv::Mat image_6 = cv::imread("6.jpg");

You chould check that image_*.empty() is not true (that means that the image has been loaded) and then do whatever you want with them.