Hi Im on mac snow leopard and test these code on xcode3.2 of the Learning OpenCV everything works fine but the image doesnt appear and in the windows. I had try to understand searching for two days what does argv[1] means, but Im still no clear. Im a newbie en C++. I had the image in the same directory where the main.cpp is #include <OpenCV/cv.h> #include <OpenCV/highgui.h> int main(int argc, char** argv) { IplImage* interest_img; CvRect interest_rect; if( argc == 7 && ((interest_img= cvLoadImage( argv[1],1) ) != 0 )) { A more easy example is here: http://books.google.cl/books?id=seAgiOfu2EIC&pg=PA17&lpg=PA17&dq=cvLoadImage%28argv[1]&source=bl&ots=hRJ5bhkAOf&sig=gyYAqZBnS6lCCXJz9Fz7vzOsF-U&hl=es&ei=dvdvS-fWG8eWtgePy_WCBg&sa=X&oi=book_result&ct=result&resnum=6&ved=0CBwQ6AEwBTgK#v=onepage&q=cvLoadImage%28argv[1]&f=false both I have test it but they dont work. Please help me