dynamic image resizing

dynamic image resizing

Hi everyone,
i am doing a website where I have a list of images (I have at least 5 images per page that need re-sizing) with a certain width. Not when I try re-sizing the window I want the smaller size to be loaded dynamically, but it is not happening. Can someone please help me? thanks in advance.

Here is a snippet of the code:

function adjustImage() {
        var winSize = $(window).width;
        var img_src = $('img').attr('src');
        
        if ((winSize > 800) && (winSize < 1400)) {
            var new_image = img_src.replace('_full', '_medium');
            $('img').attr('src', new_image);
        }
    }

HTML
<div id="right_col" class="group">
      <ul>
            <li><img src="images/arch/de_1/floor_plan_full.jpg" alt="floor_plan" class="tet"></li>
            <li><img src="images/arch/de_1/el_01_full.jpg" alt="elevation" class="tet"></li>
            <li><img src="images/arch/de_1/el_02_full.jpg" alt="elevation" class="tet"></li>
            <li><img src="images/arch/de_1/el_03_full.jpg" alt="elevation" class="tet"></li>
      </ul>
</div>