global $wp_query required for nested loop?

I’m trying to set up a small gallery that will display photos with a certain tag. This is within The Loop and before the content is output from The Loop.

Despite following the Multiple Loop instructions and patterns, the only way I could get it to work was by defining the global scope first for $id, $post, $pages, and $wp_query and then caching $wp_query. I then had to set $wp_query = $my_query. Only then would it output the_thumbnail() (that fx is in functions.php). Reversing the caching made the proper info available for the content output from The Loop (original).

I’ve scoured the documentation for evidence I need to set the scope, but there doesn’t seem to be any. This setup is being run on a page, but must have access to all posts (to find the photos with the correct tag). I’ve left “showposts” in the query because that how I tested it in its last working state.

<?php global $id, $post, $pages; ?>
     <?php  $my_id = $id;
            $my_post = $post;
            $my_pages = $pages; ?>
     <?php global $wp_query; ?>
		<?php if(is_page()) { ?>
		<?php $temp_query = $wp_query; ?>

		<?php $my_query = new WP_Query('showposts=2'); ?>
		<?php $wp_query = $my_query ?>

<ul class="thumbnails">
	<?php //if ($my_query->have_posts()) : while ($my_query->have_posts()) : $my_query->the_post(); ?>
	<?php if(have_posts()) : while(have_posts()) : the_post(); ?>
		<li id="post-<?php the_ID(); ?>">
		<a href="<?php the_permalink() ?>" title="Link to <?php the_title_attribute(); ?>"> <?php the_thumbnail(); ?></a>
		</li>
	<?php endwhile; ?>
		<?php endif;?>
</ul>
		<?php $wp_query = $temp_query; ?>
		<?php } ?>
	<p>does <?php //print_r($wp_query); ?> it print?</p>
	</div>
</div>

Thanks so much for your help!