function mytheme_get_posts( $cat_id, $offset, $posts ) { ?>

<div class="entry">
      <?php query_posts( 'cat='. $cat_id .'&offset='. $offset .'&showposts='. $posts ); ?>
      <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
         <div class="one-third column">
              <img src="<?php the_post_thumbnail();?>" alt="<?php the_title(); ?>" />
              <h4><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h4>
         </div>
      <?php endwhile; endif; // end of the loop. ?>
      <?php wp_reset_query(); ?>
      <div class="clear"></div>
</div><!--/ .entry -->

<?php }