Create an Image Grid in Xaringan - html

Question

I'm trying to learn a bit more CSS/HTML to customize xaringan slides and could use some help.
I would like to place a number of GIF's in an image grid like the one shown here into a xaringan slide.
I know that normally one can display two images side-by-side by either using .pull-left[] & .pull-right[] or by defining sections with custom CSS like this:
.left-code {
color: #777;
width: 38%;
height: 92%;
float: left;
}
.right-plot {
width: 60%;
float: right;
padding-left: 1%;
}
Then one would put the images in a xaringan slide with R code like this:
.pull-left[
<img src=figure1.jpg>
]
.pull-right[
<img src=figure2.jpg>
]
For an image grid the custom CSS would be:
.row {
display: flex;
flex-wrap: wrap;
padding: 0 4px;
}
/* Create two equal columns that sits next to each other */
.column {
flex: 50%;
padding: 0 4px;
}
.column img {
margin-top: 8px;
vertical-align: middle;
}
However, it also includes HTML code that specifies all of the images so I'm not quite sure how to integrate the two in a xaringan slide.
<div class="row">
<div class="column">
<img src="wedding.jpg">
<img src="rocks.jpg">
<img src="falls2.jpg">
<img src="paris.jpg">
<img src="nature.jpg">
<img src="mist.jpg">
<img src="paris.jpg">
</div>
<div class="column">
<img src="underwater.jpg">
<img src="ocean.jpg">
<img src="wedding.jpg">
<img src="mountainskies.jpg">
<img src="rocks.jpg">
<img src="underwater.jpg">
</div>
<div class="column">
<img src="wedding.jpg">
<img src="rocks.jpg">
<img src="falls2.jpg">
<img src="paris.jpg">
<img src="nature.jpg">
<img src="mist.jpg">
<img src="paris.jpg">
</div>
<div class="column">
<img src="underwater.jpg">
<img src="ocean.jpg">
<img src="wedding.jpg">
<img src="mountainskies.jpg">
<img src="rocks.jpg">
<img src="underwater.jpg">
</div>
</div>

Answer 1

You can do this using the extension theme here.
This theme is included the later version of xaringan so you can specify in the YAML by css: "ninjutsu". The layout should look like below:
---
title: "Split to grid in `xaringan`"
output:
xaringan::moon_reader:
css: ["ninjutsu"]
---
class: split-four
.column[
<img src="wedding.jpg">
<img src="rocks.jpg">
<img src="falls2.jpg">
<img src="paris.jpg">
<img src="nature.jpg">
<img src="mist.jpg">
<img src="paris.jpg">
]
.column[
<img src="underwater.jpg">
<img src="ocean.jpg">
<img src="wedding.jpg">
<img src="mountainskies.jpg">
<img src="rocks.jpg">
<img src="underwater.jpg">
]
.column[
other images
]
.column[
other images
]