Example of extracting thumbnails from a wordpress file

Directly run the code:
1. Add articles with thumbnails
As shown in the following figure:

1) the last one in the topic's functions. php?> Add the following code before:

// Add special thumbnail support

If (function_exists ('add _ theme_support ') add_theme_support ('post-thumbnails ');

    

// Output thumbnail address From wpdaxue.com

Function post_thumbnail_src (){
Global $ post;
If ($ values = get_post_custom_values ("thumb") {// output custom domain Image address
$ Values = get_post_custom_values ("thumb ");
$ Post_thumbnail_src = $ values [0];
} Elseif (has_post_thumbnail () {// if there is a thumbnail, the thumbnail address is output.
$ Thumbnail_src = wp_get_attachment_image_src (get_post_thumbnail_id ($ post-> ID), 'full ');
$ Post_thumbnail_src = $ thumbnail_src [0];
} Else {
$ Post_thumbnail_src = '';
Ob_start ();
Ob_end_clean ();
$ Output = preg_match_all ('//I ', $ post-> post_content, $ matches );
$ Post_thumbnail_src = $ matches [1] [0]; // get the image src
If (empty ($ post_thumbnail_src) {// if no image is in the log, a random image is displayed.
$ Random = mt_rand (1, 10 );
Echo get_bloginfo ('Template _ url ');
Echo '/images/pic/'.w.random.'.jpg ';
// If no image is in the log, the default image is displayed.
// Echo '/images/default_thumb.jpg ';
      }
};
Echo $ post_thumbnail_src;
    }
PS: The above code mainly gets the image link. The order of acquisition is as follows:

Images with a custom field of thumb> featured thumbnails> The first image in the article> random image/default image;

Random Image: make 10 images and place them in the images/pic/directory under the current topic folder. The images are in jpg format and are named after numbers 1-10, for example, 1.jpg; if you do not want to use a random image, remove "//" before the last 5th rows, and then add "//" before the last 7th or 9 rows to log out, add a default image named default_thumb.jpg to the/images/directory of the current topic. In this way, the default image is displayed.

2) add the following code to single. php to display the location of relevant articles:

<H3> Related articles

<Ul class = "related_img">

<? Php
$ Post_num = 4;
$ Exclude_id = $ post-> ID;
$ Posttags = get_the_tags (); $ I = 0;
If ($ posttags ){
$ Tags = ''; foreach ($ posttags as $ tag) $ tags. = $ tag-> term_id .',';
$ Args = array (
'Post _ status' => 'Publish ',
'Tag _ in' => explode (',', $ tags ),
'Post _ not_in '=> explode (', ', $ exclude_id ),
'Caller _ get_posts' => 1,
'Orderby' => 'Comment _ date ',
'Posts _ per_page '=> $ post_num
);

Query_posts ($ args );
While (have_posts () {the_post ();?>
<Li class = "related_box">
<Div class = "r_pic">
<A href = "<? Php the_permalink ();?> "Title =" <? Php the_title ();?> "Target =" _ blank ">
"Alt =" <? Php the_title ();?> "Class =" thumbnail "/>
</A>
</Div>
<Div class = "r_title"> <a href = "<? Php the_permalink ();?> "Title =" <? Php the_title ();?> "Target =" _ blank "rel =" bookmark "> <? Php the_title ();?> </A> </div>
</Li>
<? Php
$ Exclude_id. = ','. $ post-> ID; $ I ++;
} Wp_reset_query ();
    }

If ($ I <$ post_num ){

$ Cats = ''; foreach (get_the_category () as $ cat) $ cats. = $ cat-> cat_ID .',';
$ Args = array (
'Category _ in' => explode (',', $ cats ),
'Post _ not_in '=> explode (', ', $ exclude_id ),
'Caller _ get_posts' => 1,
'Orderby' => 'Comment _ date ',
'Posts _ per_page '=> $ post_num-$ I
);
Query_posts ($ args );
While (have_posts () {the_post ();?>
<Li class = "related_box">
<Div class = "r_pic">
<A href = "<? Php the_permalink ();?> "Title =" <? Php the_title ();?> "Target =" _ blank ">
"Alt =" <? Php the_title ();?> "Class =" thumbnail "/>
</A>
</Div>
<Div class = "r_title"> <a href = "<? Php the_permalink ();?> "Title =" <? Php the_title ();?> "Target =" _ blank "rel =" bookmark "> <? Php the_title ();?> </A> </div>
</Li>
<? Php $ I ++;
} Wp_reset_query ();
    }
If ($ I = 0) echo '<div class = "r_title"> no related articles! </Div> ';
?>
</Ul>
PS: Row 4 $ post_num = 4; indicates that four articles are called. Modify the number as needed.

For more information about css styles, see:

. Related_posts {margin-top: 5px ;}
. Related_img {width: 600px; height: 210px ;}
. Related_box {float: left; overflow: hidden; margin-top: 5px; width: 148px; border-right: 1px # eee solid}
. Related_box: hover {background: # f9f9f9}
. Related_box. r_title {width: auto; height: 72px; font-weight: 400; font-size: 14px; margin: 0 10px; overflow: hidden ;}
. Related_box. r_pic {margin: 6px}
. Related_box. r_pic img {width: 130px; height: 100px; border: 1px solid # e1e1e1; backgrou