.flex_gallery {
    display: flex;
    flex-wrap: wrap;
}

.flex_gallery>.item {
    width: 25%;
    height: 300px;
    overflow: hidden;
}

.flex_gallery>.item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    padding: 3px;
    transition: transform .3s ease-in-out;
}

.flex .flex_gallery img {
    width: 100%;
    height: 100%;
}

.flex_gallery>.item img:hover {
    transform: scale(1.1);
}