How to display only thumbnails of specific posts in jQuery carousel

Hey,

I’m wondering if anybody of you could tell me where to put this code-part:
'&cat=348, 296, 408, 353'
in this code so that only images of posts in those four categories are displayed:

<ul>
<?php $my_query = new WP_Query( array( 'posts_per_page=1' ); ?>
	<?php while ($my_query->have_posts( )) : $my_query->the_post( ); ?>
		<a href="<?php the_permalink() ?>" rel="bookmark"><?php the_post_thumbnail( array(50,50) ); ?></a>
	<?php endwhile; wp_reset_query(); ?>
</ul>
<ul>
<?php $my_query = new WP_Query( array( 'posts_per_page' => 1, 'offset' => 1 ) ); ?>
	<?php while ($my_query->have_posts()) : $my_query->the_post(); ?>
		<a href="<?php the_permalink() ?>" rel="bookmark"><?php the_post_thumbnail( array(50,50) ); ?></a>
<?php endwhile; wp_reset_query(); ?>
</ul>