@stujmiller you can add an if statement to the slide-image. Find the active-thumb code in the main-product.liquid (there’s two, do the code to both), then add {% if product.media.size > 1 %} active-thumb {% endif %}
Code should look like below
<img class=“slide-image {% if forloop.first %} {% if product.media.size > 1 %} active-thumb {% endif %} {% endif %}”
Let me know