recent posts for different categories

If the blog / portfolio items are grouped into categories, you can do this at the top of your template file:

<?php
$portfolio_query = new WP_Query('posts_per_page=3&category_name=portfolio'); // note 'portfolio' is the category slug
$blog_query = new WP_Query('posts_per_page=3&category_name=blog'); // note 'blog' is the category slug
?>

Then in your markup:

<?php if ($portfolio_query->have_posts()) : ?>
<div id="recent">
    <div id="recent-work">
            <p><span>Recent Work</span></p>
            <?php while ( $portfolio_query->have_posts() ) : $portfolio_query->the_post(); ?>
            <a href="https://wordpress.stackexchange.com/questions/55832/<?php the_permalink(); ?>"><img src="http://lorempixel.com/130/130/" alt="Click for more information" /></a>
            <?php endwhile; ?>
                    <div class="next"><a href="#"><img src="img/next.png" alt="Click for more information" /></a></div>
    </div><!-- end recent-work -->
<?php endif; ?>
    <div class="divider">
            <img src="img/divider.png" alt="Section divider" />
    </div><!-- end divider -->

<?php // repeat the whole if clause here for the blog posts, just replace $blog_query with $portfolio_query ?>