Расположите миниатюры внизу с помощью Fancybox

$('[data-fancybox = "images"]').fancybox({
  thumbs: {
    autoStart: true,
    axis: 'x'
  }
})

.fancybox-thumbs {
  top: auto;
  width: auto;
  bottom: 0;
  left: 0;
  right: 0;
  height: 95px;
  padding: 10px 10px 5px 10px;
  box-sizing: border-box;
  background: rgba(0, 0, 0, 0.3);
}

.fancybox-show-thumbs .fancybox-inner {
  right: 0;
  bottom: 95px;
}

<script src = "//code.jquery.com/jquery-3.3.1.min.js"></script>
<link rel = "stylesheet" href = "https://cdn.jsdelivr.net/gh/fancyapps/[email protected]/dist/jquery.fancybox.min.css" />
<script src = "https://cdn.jsdelivr.net/gh/fancyapps/[email protected]/dist/jquery.fancybox.min.js"></script>

<h2>fancyBox v3.3 - Thumbnails at the bottom</h2>
<hr class = "my-5" />
<p class = "imglist">
  <a href = "https://source.unsplash.com/juHayWuaaoQ/1500x1000" data-fancybox = "images">
    <img src = "https://source.unsplash.com/juHayWuaaoQ/240x160" />
  </a>
  <a href = "https://source.unsplash.com/eWFdaPRFjwE/1500x1000" data-fancybox = "images">
    <img src = "https://source.unsplash.com/eWFdaPRFjwE/240x160" />
  </a>
  <a href = "https://source.unsplash.com/i2KibvLYjqk/1500x1000" data-fancybox = "images">
    <img src = "https://source.unsplash.com/i2KibvLYjqk/240x160" />
  </a>
  <a href = "https://source.unsplash.com/RFgO9B_OR4g/1500x1000" data-fancybox = "images">
    <img src = "https://source.unsplash.com/RFgO9B_OR4g/240x160" />
  </a>
  <a href = "https://source.unsplash.com/7bwQXzbF6KE/1500x1000" data-fancybox = "images">
    <img src = "https://source.unsplash.com/7bwQXzbF6KE/240x160" />
  </a>
  <a href = "https://source.unsplash.com/NhU0nUR7920/1500x1000" data-fancybox = "images">
    <img src = "https://source.unsplash.com/NhU0nUR7920/240x160" />
  </a>
  <a href = "https://source.unsplash.com/ndjyaOp0fOc/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/ndjyaOp0fOc/240x160" />
  </a>
  <a href = "https://source.unsplash.com/A-fubu9QJxE/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/A-fubu9QJxE/240x160" />
  </a>
  <a href = "https://source.unsplash.com/rkkr6-2I4sg/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/rkkr6-2I4sg/240x160" />
  </a>
  <a href = "https://source.unsplash.com/mr_Tg4SI66A/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/mr_Tg4SI66A/240x160" />
  </a>
  <a href = "https://source.unsplash.com/YEsedBccUEA/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/YEsedBccUEA/240x160" />
  </a>
  <a href = "https://source.unsplash.com/Hw62tzAkXXE/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/Hw62tzAkXXE/240x160" />
  </a>
  <a href = "https://source.unsplash.com/Lzx4J_Pb3sk/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/Lzx4J_Pb3sk/240x160" />
  </a>
  <a href = "https://source.unsplash.com/cZVthlrnlnQ/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/cZVthlrnlnQ/240x160" />
  </a>
  <a href = "https://source.unsplash.com/vddccTqwal8/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/vddccTqwal8/240x160" />
  </a>
  <a href = "https://source.unsplash.com/Sj5efgWguDs/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/Sj5efgWguDs/240x160" />
  </a>
  <a href = "https://source.unsplash.com/Y7y7fe8hrh0/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/Y7y7fe8hrh0/240x160" />
  </a>
  <a href = "https://source.unsplash.com/sYegwYtIqJg/1600x900" data-fancybox = "images" data-type = "image">
    <img src = "https://source.unsplash.com/sYegwYtIqJg/240x160" />
  </a>
</p>