<p>This plugin will scan your thumbnail-less posts and look for a suitable image to use as a thumbnail.<br />
It will look for images linked in the post content and will download and add them to the local library.<br />
Post scanning is performed only when <code>the_post_thumbnail</code> or <code>get_the_post_thumbnail</code> are called for<br />
that particular post.</p>
<p>So you designed your new thumbnail-based template, but you have tons of thumbnail-less posts and<br />
don’t want to spend too much time on scraping your old posts for a thumbnail picture. Maybe you<br />
think you will probably forget to set a thumbnail for your new posts. Maybe both, as was my case :).</p>
<p>When a thumbnail for a post is queried and nothing is found this plugin will scrape the post for<br />
an <code><img></code> tag and its <code>href</code> property. Once a suitabile image is found (based on the configured<br />
settings), it will be downloaded ad set as the post thumbnail. If no suitable image is found,<br />
a default one will be used.</p>
<p>This plugin is still in early development state. It just covers my needs (see the “To do” section<br />
for more details). It has been tested only with wordpress 3.0.1, but should work also with 2.9,<br />
since I used similar code with 2.9 (even if it was included in my template’s <code>functions.php</code>).</p>
<p>The plugin is not supported. This doesn’t mean that I will not look into submitted bugs. Anyway,<br />
don’t expect prompt answers, since this is done in my spare time.</p>
<h3>To do</h3>
<p>Many things should be done in future releases. Here are some:</p>
<ul>
<li>Current version always downloads selected linked images. This works good with images hosted on external sites.<br />
If your posts link to images hosted in your media library, you will end up with two images.</li>
<li>A more user friendly name should be used for images added to the library (e.g. Thumbnail for post …)</li>
<li>Somewhere, a button to reset the “previously scanned” status of all posts should be provided (on current version,<br />
you cas set or reset it for single posts in the edit page.</li>
<li>“previously scanned” status should probably be reset (or at least you should be asked to) when publishing a<br />
updating an existing post</li>
</ul>
<p>More ideas are wellcome.</p>


Automatic Thumbnail Generator

Automated on-demand generation of posts thumbnails.

Yuriy Stepanov

<p>The pluginplug-in, with two additional SQL queries, joins the original data sample $wp_query->posts all meta fields, all files and images, for each image the direct url to small, medium, and large image is formed. There’s no need to use functions the_post_thumbnail  and get_post_meta.</p>
<h4>How it works</h4>
<p>So let’s say we go to the home page of our blog, WordPress gives us a list of the latest 10 records. Let me remind you these are already in the global object in the array $wp_query-> posts. Let’s begin from creating a list of ID (number of records to which they are stored in the database).</p>
<h4>Form the first SQL query:</h4>
<ul>
<li>$query = “SELECT $wpdb->posts.* FROM $wpdb->posts WHERE  $wpdb->posts.post_parent IN(’21’,’29’,’30’,’35’,’38’,’42’,’46’,’48’,’49’,’55’) AND $wpdb->posts.post_parent<br />
AND $wpdb->posts.post_type = ‘attachment'”;</li>
</ul>
<p>A normal translation is «find all the child entries for entries with the numbers (’21 ‘, ’29?, ’30 ‘, ’35?, ’38 ‘, ’42?, ’46 ‘, ’48?, ’49 ‘, ’55 ‘)». And the type of records required to be «attachment». That is, in short, we find all the files (attachment) which we downloaded for our 10 entries.</p>
<p>Again we form a list of ID: the first 10 ID entries and add the ID of files (attachments). Attachments as ordinary records are stored in one table – wp_posts.</p>
<h4>Now we use the function update_meta_cache:</h4>
<ul>
<li>$all_meta = update_meta_cache(‘post’, $ar_all_id);</li>
</ul>
<p>$ar_all_id – here are the original recordings and attachments</p>
<p>So everything just gets in the cache and subsequent calls get_post_meta will derive value from the cache. The rest is a matter of technique – the data must be carefully arranged, not mixing anything up. All meta fields are added to the $post->meta array, and files into an $post->files array and files are immediately sorted by number order (when downloading it, you can specify the sort order).<br />
In addition, for each file, if it is an image, the full path to the thumbnails is calculated: small (thumbnail), average (medium) and the complete picture (full).</p>
<h4>WordPres 4:</h4>
<p>The default filter is only connected to the main query using is_main_query().<br />
Does not work in is_admin() or is_page().</p>
<p><a href="http://bugacms.com/wpEn/all-inclusive/" rel="nofollow ugc">Home page</a><br />
<a href="http://bugacms.com/wpRu/all-inclusive/" rel="nofollow ugc">Русская страница</a></p>
<h3>A brief Markdown Example</h3>
<p><a href="http://bugacms.com/wpEn/all-inclusive/" rel="nofollow ugc">More PHP code Examples</a><br />
<a href="http://bugacms.com/wpRu/all-inclusive/" rel="nofollow ugc">Больше примеров</a></p>


All Inclusive

The pluginplug-in, with two additional SQL queries, joins the original data sample $wp_query->posts all meta fields, all files and images.

Automatic Thumbnail Generator vs All Inclusive