Multiple loop working, function inside isn't

I'm using this piece of code I found (http://impnerd.com/wordpress-hack-add-post-images-to-your-homepage) to display the first image uploaded to a post on the homepage next to the excerpts of posts. I'm doing this outside the main loop on the homepage, and have been having problems. When I do rewind_posts() to get the same loop results, it works fine, but when I try to create a different loop, this code snippet breaks down:

$images =& get_children( 'post_type=attachment&post_mime_type=image&post_parent=' . $post->ID );

if ($images) 
{
  $keys = array_keys($images);
  $num = $keys[0];
  $firstImageSrc = wp_get_attachment_thumb_url($num);
  echo "<li><img src=\"{$firstImageSrc}\" width=\"288\" height=\"216\"  alt=\"\" title=\"\" /></li>";
} 

I have tried the methods in The_Loop#Multiple_Loops_in_Action in the docs, and they work, meaning I can get normal output after the loop, but my snippet above doesn't work. Any idea if there is a conflicting method call or something that's going on that's stopping it from working? Would appreciate some help, thanks!

To be more specific:

<?php $my_query = new WP_Query('category_name=Daily Photo&showposts=1');
while ($my_query->have_posts()) : $my_query->the_post();
$do_not_duplicate = $post->ID; ?>
<p>a</p>
<?php $images =& get_children( 'post_type=attachment&post_mime_type=image&post_parent=' . $post->ID );
if ($images) {
$keys = array_keys($images);
$num = $keys[0];
$firstImageSrc = wp_get_attachment_thumb_url($num);
echo "<li><img src=\"{$firstImageSrc}\" width=\"288\" height=\"216\"  alt=\"\" title=\"\" /></li>";} ?>
<?php endwhile; ?>

will output <p>a</p>, but not the <li><img /></li> code I need in the snippet. Whereas if I use rewind_posts();, everything works, and I get the <li><img /></li> code, but I don't want to use the same loop that I had been using previously. I'm using this to display a daily photo in the sidebar, that pulls from the "Daily Photo" category. I will exclude Daily Photos from the main loop, and only want to use them to draw images from in that sn开发者_StackOverflowippet.

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Try removing the if statement for starters. Remove any references to images and see if it outputs your html without the image source. If that's the case then images isn't getting properly assigned and it's never executing the code.

$images =& get_children( 'post_type=attachment&post_mime_type=image&post_parent=' . $post->ID );

This code checks to see if there is an image uploaded to the gallery.

Now you need to troubleshoot the above statement and see why you're not getting any images.

Also, it looks like there is a plugin to do just this if you don't want to continue messing with the code.

Another thing to keep in mind is that this code is pretty old and may not be compatible with your version of wordpress.