Hope this is your structure:
<ul>
<li>
<div ><img.. /><p>text</p></div>
</li>
<li>
<div ><img.. /><p>text</p></div>
</li>
<li>
<div ><img.. /><p>text</p></div>
</li>
</ul>
By default, it will be add one after another row:
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if you want to make it vertical, just add float left to li, give width and height, make sure that content will not break the width:
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| | |
li
{
display:block;
float:left;
width:300px; /* adjust */
height:150px; /* adjust */
padding: 5px; /*adjust*/
}