chromeos/components/personalization_app/resources/untrusted/images_grid.html

<style include="common-style untrusted-style">
  :host {
    margin: 12px 0;
  }
</style>
<iron-list scroll-target="document" grid items="[[images_]]">
  <template>
    <div class="photo-container">
      <div class="padding-fix">
        <img data-id$="[[item.assetId]]" src="[[item.url.url]]"
            on-click="onImageClicked_">
      </div>
    </div>
  </template>
</iron-list>