I want to show more than one photo

<div class="col-lg-6">
    <div class="cz-product-gallery">
        <div class="cz-preview order-sm-2">
         <?php $i = 0;
         foreach ($prdGal as $galeri) {
            $i++; ?>
            <div class="cz-preview-item <?php if ($i == 1) {
                echo "active";
            } ?>" id="galeri_<?= $galeri->id ?>">
            <img class="cz-image-zoom" src="<?= base_url(firstGalleryItem($product->galeri_uniq)) ?>" data-zoom="<?= base_url(firstGalleryItem($product->galeri_uniq)) ?>" alt="<?= $product->urun_ad ?>">
            <div class="cz-image-zoom-pane"></div>
        </div>
    <?php } ?>
</div>

The above code is showing bigphotos

<div class="cz-thumblist order-sm-1">
    <?php $i = 0;
    foreach ($prdGal as $gal) {
        $i++; 
        $activeClass = $i == 1 ? "active" : "";?>
        <a class="cz-thumblist-item <?php if ($i == 1) {
            echo "active";
        } ?>" href="#galeri_<?= $gal->id ?>">
        <img src="<?= base_url(firstGalleryItem($product->galeri_uniq)) ?>"
        alt="<?= $product->urun_ad ?>">
    </a>
<?php } ?>
</div>

This code shows the small version of the big photos.

The problem here is that even though I upload 2 different photos, I can only take 1 photo. How can I show 2 different photos?