revision:
<div class="grid_A"> <div> <h3>resize with HTML</h3> <img src="../images/1.jpg" width="400" height="300" alt="evening" style="margin-left:5vw;"> </div> <div> <h3>resize with CSS</h3> <img class="resize" src="../images/1.jpg" alt="evening" style="margin-left:1vw;"> <img class="resize_a" src="../images/1.jpg" alt="evening" style="margin-left:1vw;"> </div> </div> <style> img.resize{width: 30vw; height: 20vw;} img.resize_a{max-width: 30%; max-height: 30%;} </style>
<div > <div class="box"> <div class="img-container"><img src="../images/1.jpg" alt="evening"></div> </div> <div class="box"> <div class="img-container"><img src="../images/2.jpg" alt="beach"></div> </div> <div class="box-vw"> <div class="img-container"><img src="../images/3.jpg" alt="bath"></div> </div> </div> <style> .box, .box-vw {background-color: green;border-radius: 1vw; overflow: hidden;margin-bottom: 1.5vw;} .box:nth-of-type(2) {width: 26vw; } .box-vw .img-container {width: 100vw; height: 66.620879vw; padding-bottom: inherit;} .img-container {width: 100%; height: 0;/* Aspect ratio of picture*/padding-bottom: 66.620879%;} img {width: 100%;} </style>