Benden birkaç sani önce yazmışsın. Ben halletmiştim teşekkür ederim. Ayrıca tam çalışır kodları ekleyeyim thumbnail vb içerisinde var.

function the_content_limit($max_char, $more_link_text = '', $stripteaser = 0, $more_file = '') {
    $content = get_the_content($more_link_text, $stripteaser, $more_file);
    $content = apply_filters('the_content', $content);
    $content = str_replace(']]>', ']]>', $content);
    $content = strip_tags($content);

   if (strlen($_GET['p']) > 0) {
      echo "";
      echo $content;
      echo "&nbsp;<a href='";
      the_permalink();
      echo "'>"."Devam &rarr;</a>";
      echo "";
   }
   else if ((strlen($content)>$max_char) && ($espacio = strpos($content, " ", $max_char ))) {
        $content = substr($content, 0, $espacio);
        $content = $content;
        echo "";
        echo $content;
        echo "...";
        echo "&nbsp;<a href='";
        the_permalink();
        echo "'>"."Devam &rarr;</a>";
        echo "";
   }
   else {
      echo "";
      echo $content;
      echo "&nbsp;<a href='";
      the_permalink();
      echo "'>"."Devam &rarr;</a>";
      echo "";
   }
}

function get_thumbnail($postid=0, $size='full') {
    if ($postid<1)
    $postid = get_the_ID();
    $thumb = get_post_meta($postid, "thumbnail", TRUE);
    if ($thumb != null or $thumb != '') {
        echo $thumb;
    }
    elseif ($images = get_children(array(
        'post_parent' => $postid,
        'post_type' => 'attachment',
        'numberposts' => '1',
        'post_mime_type' => 'image', )))
        foreach($images as $image) {
            $thumbnail=wp_get_attachment_image_src($image->ID, $size);
            ?>
<?php echo $thumbnail[0]; ?>
<?php
        }
    else {
        echo get_bloginfo ( 'stylesheet_directory' );
        echo 'resim-bulamadim.gif';
    }
   
}
?>