mw-100
bootstrap5.css
bootstrap5.css
.mw-100 {
max-width: 100% !important;
}
html bootstrap5 Sample
最大幅を指定する：mw-100
<img class="mw-100" src="https://via.placeholder.com/318x180/FFFF00/000000?text=img" alt="">
.mw-100 {
max-width: 100% !important;
}
<img class="mw-100" src="https://via.placeholder.com/318x180/FFFF00/000000?text=img" alt="">