I'm in a situation since 3 day and I don't have found any answer to my question : how have div on the same width (containing images with a width of 320px) on the column (that's done) but not organize in line ?
Let me join a little sketch to explain that : at the left, it's what I've. At the right, it's what I want. (the second line is for the "media screen" when reducing the width of the screen/navigator : so have 4 to 3 to 2 to 1 (and vice versa). take care of the number of boxes) :

To explain how I've obtain this right part, here are the code :
html:
<div class="box">
<a href="#"><img src="#" alt=""/></a>
</div>
Simply a succession of this class, it can be directly on the body. The box is important because maybe I'll have to had tittles or others things.
css:
.box {
    position: relative;
    float: left;
    min-width: 340px;
    max-width: 24.80%;
    width: 24.79%;
    margin: 20px 0px 20px 0px;
}
@media only screen and (max-width: 1800px) {
    .box {
        min-width: 360px;
        max-width: 33%;
        width: 33%;
    }   
}
To complete this question, here are a restriction : it had to be dynamic and generic (so like that, I just have to make a copy of a div and replace the link of the image (that's before adding php and js), or add anything I want).
 
     
    