Here are some starts for you:
Embed a mediashare gallery anywhere on the site:
<div ><!--[ pnmodfunc modname=mediashare func=list key=$keyname tpl=profile order=modified orderdir=desc pageSize=50]--></div>
This will insert a div with a row of image thumbnails...
NOTE: Read this thread as it will explain "pageSize=50"
http://www.elfi…pic&topic=3483
You will then need a new mediashare template. Here's mine-it's called "mediashare_user_profile.html" and it simply displays the thumbnails. Whe clicked the lightbox feature is enacted to show the full image.
<!--[include file=mediashare_include_lightbox.html]-->
<!--[foreach from=$items item=item]-->
<a href="<!--[mediashare_mediaUrl src=originalRef mediaItem=$item.media]-->" rel="lightbox" title="<!--[$item.media.title]-->">
<!--[mediashare_mediaItem src=$item.media.thumbnailRef title=$item.media.title mediaHandler=$item.media.mediaHandler isThumbnail="1" id="media-`$item.media.id`" class="thumbnail" ]--></a>
<!--[/foreach]-->
As far as having rotating background images from a mediashare gallery there might be an easier way to get them... perhaps you should look at the way the random image block is created and use that as an example for building your own smarty plugin to retrieve a random image and output it as a variable. You could then use that variable (an image) on the page...