调用图片

//1. 首先在 function.php 中新增函数 catch_that_image
function catch_that_image() {
  global $post, $posts;
  $first_img = '';
  ob_start();
  ob_end_clean();
  $output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $post->post_content, $matches);
  $first_img = $matches [1] [0];
  if(empty($first_img)){ //Defines a default image
    $first_img = "http://yourwebsite/default.jpg";
  }
  return $first_img;
}

//1.1 function.php的另外一种方法
function catch_the_image( $id ) {
  // global $post, $posts;
  $first_img = '';
  // 如果设置了缩略图
  $post_thumbnail_id = get_post_thumbnail_id( $id );
  if ( $post_thumbnail_id ) {
    $output = wp_get_attachment_image_src( $post_thumbnail_id, 'large' );
    $first_img = $output[0];
  }
  else { // 没有缩略图，查找文章中的第一幅图片
    ob_start();
    ob_end_clean();
    $output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $post->post_content, $matches);
    $first_img = $matches [1] [0];
    if(empty($first_img)){ // 既没有缩略图，文中也没有图，设置一幅默认的图片
      $first_img = "http://yourdomain.tld/images/default.jpg";
    }
  }
  return $first_img;
}
//2. 调用 <img src="<?php echo catch_that_image() ?>" alt="" /> //3. 循环调用 <?php if (have_posts()) : ?> <?php query_posts('cat=3' . $mcatID. '&caller_get_posts=1&showposts=6'); ?> <?php while (have_posts()) : the_post(); ?> <li> <p><a href="<?php the_permalink() ?>" ><img src="<?php echo catch_that_image() ?>" alt="" /></a></p> </li> <?php endwhile;?> <?php else : ?> <?php endif; ?>