Implementation of random display of thumbnails in WordPress articles

In our development and production of wordpress theme, most of us will do the home page and list page to automatically call the first picture in the article as a thumbnail. If there is no thumbnail in the article, the default thumbnail will be displayed, but this will repeat a large number of default thumbnails, which is very impressive to the user experience. The following code just solves the problem of random display of thumbnails in WordPress articles, which can Let the article thumbnail random display, if there is a thumbnail will call the thumbnail, no thumbnail will randomly select a thumbnail.

If you don’t want the thumbnail to be displayed randomly, you can also automatically get the first picture in the article as the thumbnail. For specific tutorial, please check out this article “WordPress automatically gets the first picture in the article as a thumbnail”

There are many similar tutorials on the Internet, but several tested codes are invalid, and even syntax errors. The following is a version of wptootutorial website available for pro testing:

//Support external link thumbnail
if ( function_exists('add_theme_support') )
 add_theme_support('post-thumbnails');
function catch_first_image() 
{
	global $post, $posts;$first_img = '';
	ob_start();
	ob_end_clean();
	$output = preg_match_all('/<img.+src=['"]([^'"]+)['"].*>/i', $post->post_content, $matches);
	$first_img = $matches [1] [0];
	//Judge whether the picture is too small
	if(!empty($first_img))
	{
		$image_size = getimagesize($first_img);
		$image_width = $image_size[0];
	}
	//If the first image does not exist or is too small,The random picture is returned
	if(empty($first_img) || $image_width<50){
		$first_img = '';
		//from2Random selection in a picture,It can be set according to the number of pictures
		$random = mt_rand(1, 2);
		echo get_bloginfo ( 'stylesheet_directory' );
		echo '/images/random/'.$random.'.JPG';
		}
  return $first_img;
}

usage method

1. Copy the code above and paste it into the theme functions.php Medium

2. Create a new / images / random / directory in the theme and upload some pictures you like. Rename them to 1, 2, 3, 4, 5.jpg.

3. Add the following code where you want to show the thumbnail

<?php echo catch_first_image(); ?>
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