Justified

<div class="gallery-fg" data-design="justified">

    <div class="item-fg">
        <img src="images/1.png" alt="">
        <div class="caption">Some caption goes here</div>
        <a href="images/1.png"></a>
    </div>

    <div class="item-fg">
        <img src="images/2.png" alt="">
        <a href="images/2.png"></a>
    </div>

...

</div>

Grid

<div class="gallery-fg" data-design="grid">

    <div class="item-fg">
        <img src="images/1.png" alt="">
        <div class="caption">Some caption goes here</div>
        <a href="images/1.png"></a>
    </div>

    <div class="item-fg">
        <img src="images/2.png" alt="">
        <a href="images/2.png"></a>
    </div>

...
</div>

Masonry

<div class="gallery-fg" data-design="masonry">

    <div class="item-fg">
        <img src="images/1.png" alt="">
        <div class="caption">Some caption goes here</div>
        <a href="images/1.png"></a>
    </div>

    <div class="item-fg">
        <img src="images/2.png" alt="">
        <a href="images/2.png"></a>
    </div>

...
</div>

Fullwidth

<div class="gallery-fg" data-design="fullwidth">

    <div class="item-fg">
        <img src="images/1.png" alt="">
        <div class="caption">Some caption goes here</div>
        <a href="images/1.png"></a>
    </div>

    <div class="item-fg">
        <img src="images/2.png" alt="">
        <a href="images/2.png"></a>
    </div>

...
</div>