This Shopify section will show the product photos in a collection that are smaller than the threshold set.

collection-template-photos.liquid

<section class="section__wrapper section">

  <div class="container content">

    <h1>{{collection.title | escape }}</h1>

    {% if collection.description != blank %}
    <div>{{ collection.description }}</div>
    {% endif %}

    <h2>Current Threshold - <strong>{{ section.settings.size-limit }} pixels</strong></h2>
    <p>&nbsp;</p>

    {% paginate collection.products by 50 %}

    {% for product in collection.products %}
    <div>
      <h2><a href="https://sbp-electricals.myshopify.com/admin/products/{{ product.id }}" target="_blank">{{ product.title }} | {{ product.vendor }} | {{ product.type }}</a></h2>
    </div>
    {% for image in product.images %}
    {% unless image.width > section.settings.size-limit or image.height > section.settings.size-limit %}
    <p>
      <a href="{{ product.url }}" target="_blank"><img src="{{ image.src | product_img_url: 'original' }}"></a>{{ image.width }} x {{ image.height }}
    </p>
    {% endunless %}
    {% endfor %}
    {% endfor %}
    <p>&nbsp;</p>
    <div>
      {{ paginate | default_pagination: next: 'Next', previous: 'Previous' }}
    </div>

    {% endpaginate %}
    <p>&nbsp;</p>
  </div>

</section>

{% style %}

.container { display: block; }

{% endstyle %}

{% schema %}

{
"name":"Product Photos",
"settings":[
{
"type": "range",
"id": "size-limit",
"label": "Show photos smaller than",
"min":       100,
"max":        2000,
"step":       25,
"default": 600
}
]
}
{% endschema %}