* {
    margin:0px;
    padding:0px;
    box-sizing: border-box;
}

.row{
    display:flex;
    flex-wrap: wrap;
}
.column{
    width:50vw;
}
.column img {
    width:100%;
    vertical-align: middle;
    border:1px solid lightgray;
}

@media (min-width:800px){
    .column{
        width:25vw;
    }
}