This example assumes that the content form has a multi-file field called 'background_pictures'.
{getfield field=background_pictures shuffle=true var=background_pictures}
<ul class="fadeBkg">
{foreach from=$background_pictures item=background_picture}
<li><img src="{$background_picture.file}" alt="{$background_picture.legend|escape}" title="{$background_picture.legend|escape}" /></li>
{/foreach}
</ul>