JSFiddle - React, Tailwind, and code Playground

HTML

<div class="tiles">
    <div class="tile">
        <img src="http://beerhold.it/200/200" class="t1x1">
        <img src="http://beerhold.it/100/100" class="t1x1">
        <img src="http://beerhold.it/250/125" class="t2x1">
    </div>
    <div class="tile">
        <img src="http://beerhold.it/100/200" class="t1x2">
        <img src="http://beerhold.it/120/240" class="t1x2">
    </div>
    <div class="tile">
        <img src="http://beerhold.it/200/100" class="t2x1">
        <img src="http://beerhold.it/400/200" class="t2x1">
    </div>
</div>

CSS

.tiles {
    display: flex;
    overflow: hidden;
}
.tile {
    flex: 0 0 calc(100% / 3);
    float: left;
    width: 33.33%;
}
img {
    float: left;
}
.t1x1, .t1x2 {
    width: 50%;
}
.t2x1 {
    width: 100%;
}