Issue with image in GitHub pages, but it works locally

I have a GitHub pages site I'm working on, and one one page, the image won't display. It works fine when I load the page locally.

Here's the site where it won't load - http://ibldynamics.com/exercises/ex10_36.html And the code I have is

   <div>    
    <h1>Chapter 10, Explorations 36-40</h1>
    <p> Print out the figure below to assist with these explorations. This is Figure 10.1 in your textbook.
    <img src="../images/Sarkpic1.png" class="img-fluid" alt="Sarkpic1"></p>

</div>

I have another page with an image, and it work's fine - http://ibldynamics.com/exercises/fig6_3.html

And the code I'm using there is

   <div>    
    <h1>Chapter 6, Figure 6.3</h1>
    <p> Print out the image below, and use it to assist with explorations 43-47 in the text.
    <img src="../images/logisticPic2.png" class="img-fluid" alt="logisticPic2"> </p>

</div>

All preamble stuff was copied and pasted, it's all identical. Any ideas? I've tried multiple browsers, so that's not it.