<img src="img/derp/2.jpg"/>

//DETECT THE INITIAL SCREEN WIDTH AND CHANGE THE PATH TO LOAD THE APPROPRIATE IMAGES

    if ($(window).width() < 960) {
        $("img").each(function() {
            $(this).attr("src", $(this).attr("src").replace("img/derp", "img/port"));
        });
    }

    else {
        $("img").each(function() {
              $(this).attr("src", $(this).attr("src").replace("img/derp", "img/land"));
        });

    }


//DETECT THE CHANGED SCREEN WIDTH AND SWITCH THE IMAGE PATH IF NECESSARY

$(window).on('resize', function() {

        if ($(window).width() < 960) {
            $("img").each(function() {
                  $(this).attr("src", $(this).attr("src").replace("img/land", "img/port"));
            });

        } else {
            $("img").each(function() {
                  $(this).attr("src", $(this).attr("src").replace("img/port", "img/land"));
            });
        }
});