If you want text close to an image like a caption:
Code:
CSS:
div.image {margin: 2em auto; font-size:.8em; text-align:center}
div.image img {display:block; margin:0}
HTML:
<div class="image">
<img alt="" src="yourimage.png"/>
Whatever text you want.
</div>
If you want to have the text flow around an image, then just use the float property.
Code:
CSS:
div.image {float:left; padding:5px; width:20%}
HTML:
<div class="image">
<img alt="" src="yourimage.png"/>
</div>
<p>Some paragraph of text.</p>
<p>Some paragraph of text.</p>
<p>Some paragraph of text.</p>
This is for basic ePub2 which should give `universal’ support. There are other, fancier, techniques for ePub3 with less support.