Timur Kamaev

Convenient way to create post thumbnails on the fly without server overload.
The best alternative to scripts like “thumbnail.php”.
Supports Multisite.
<h3>Usage</h3>
The plugin for developers firstly, because it don’t do anything after install. In order to the plugin begin to work, you need use one of plugin function in your theme or plugin. Example:
<pre><code><?php echo kama_thumb_img( 'w=150 &h=150' ); ?>
</code></pre>
Using the code in the loop you will get ready thumbnail IMG tag. Plugin takes post thumbnail image or find first image in post content, resize it and create cache. Also creates custom field for the post with URL to original image. In simple words it cache all routine and in next page loads just take cache result.
You can make thumbs from custom URL, like this:
 
The <code>URL_TO_IMG</code> must be from local server: by default, plugin don’t work with external images, because of security. But you can set allowed hosts on settings page: <code>Settings > Media</code>.
All plugin functions:
<pre><code>// return thumb url URL
echo kama_thumb_src( $args, $src );

// return thumb IMG tag
echo kama_thumb_img( $args, $src );

// return thumb IMG tag wraped with <a>. A link of A will leads to original image.
echo kama_thumb_a_img( $args, $src );

// to get image width or height after thumb creation
echo kama_thumb( $optname );
// ex:
echo '<img src="'. kama_thumb_src('w=200') .'" width="'. kama_thumb('width') .'" height="'. kama_thumb('height') .'" alt="" />';
</code></pre>
Parameters:
<ul>
<li>
$args (array/string) 
Arguments to create thumb. Accepts:
<ul>
<li>
w | width 
(int) desired width.
</li>
<li>
h | height 
(int) desired height.
if parameters <code>w</code> and <code>h</code> not set, both of them became 100 – square thumb 100х100 px.
</li>
<li>
notcrop 
(isset) if set <code>crop</code> parameter become false – <code>crop=false</code>.
</li>
<li>
crop 
(isset) Control image cropping. By default always <code>true</code>.
To disable cropping set here <code>false/0/no/none</code> or set parameter <code>'notcrop'</code>. Then image will not be cropped and will be created as small copy of original image by sizes settings of one side: width or height – here plugin select the smallest suitable side. So one side will be as it set in <code>w</code> or <code>h</code> and another side will be smaller then <code>w</code> or <code>h</code>.
Cropping position
Also, you can specify string: <code>'top'</code>, <code>'bottom'</code>, <code>'left'</code>, <code>'right'</code> or <code>'center'</code> and any other combinations of this strings glued with <code>/</code>. Ex: <code>'right/bottom'</code>. All this will set cropping area:
<ul>
<li><code>'left', 'right'</code> – horizontal side (w)</li>
<li><code>'top', 'bottom'</code> – vertical side (h)</li>
<li><code>'center'</code> – for both sides (w and h)</li>
</ul>
When only one value is set, the other will be by default. By default: <code>'center/center'</code>.
Examples:
<pre><code>// image will be reduced by height, and width will be cropped.
// "right" means that right side of image will be shown and left side will be cut.
kama_thumb_img('w=200 &h=400 &crop=right');

// image will be redused by width, and height will be cropped.
// "top" means that the top of the image will be shown and bottom side will be cut.
kama_thumb_img('w=400 &h=200 &crop=top');

// you can specify two side position at once, order doesn't matter
kama_thumb_img('w=400 &h=200 &crop=top/right');
</code></pre>
Reduce image by specified side
In order to get not cropped proportionally rediced image by specified side: by width or height. You need specify only width or only height, then other side will be reduced proportional. And no cropping will appear here.
<pre><code>kama_thumb_img('w=200');
</code></pre>
So, width of our image will be 200, and height will be as it will… 
Теперь ширина всегда будет 200, а высота какая получится… And the picture will be always full, without cropping.
</li>
<li>
q | quality 
(int) jpg compression quality (Default 85. max.100)
</li>
<li>
stub_url 
(string) URL to no_photo image.
</li>
<li>
alt 
(str) alt attr of img tag.
</li>
<li>
title 
(str) title attr of img tag.
</li>
<li>
class 
(str) class attr of img tag.
</li>
<li>
style 
(str) style attr of img tag.
</li>
<li>
attr 
(str) Allow to pass any attributes in IMG tag. String passes in IMG tag as it is, without escaping.
</li>
<li>
a_class 
(str) class attr of A tag.
</li>
<li>
a_style 
(str) style attr of A tag.
</li>
<li>
a_attr 
(str) Allow to pass any attributes in A tag. String passes in A tag as it is, without escaping.
</li>
<li>
no_stub 
(isset) don’t show picture stub if there is no picture. Return empty string.
</li>
<li>
yes_stub 
(isset) show picture stub if global option in option disable stub showing, but we need it…
</li>
<li>
post_id | post 
(int|WP_Post) post ID. It needs when use function not from the loop. If pass the parameter plugin will exactly knows which post to process. Parametr ‘post’ added in ver 2.1.
</li>
<li>
attach_id 
(int) ID of wordpress attachment image. Also, you can set this parametr by pass attachment ID to ‘$src’ parament – second parametr of plugin functions: <code>kama_thumb_img('h=200', 250)</code> or <code>kama_thumb_img('h=200 &attach_id=250')</code>
</li>
<li>
allow 
(str) Which hosts are allowed. This option sets globally in plugin setting, but if you need allow hosts only for the function call, specify allow hosts here. Set ‘any’ to allow to make thumbs from any site (host).
</li>
</ul>
</li>
<li>
$src 
(string) URL to any image. In this case plugin will not parse URL from post thumbnail/content/attachments.
If parameters passes as array second argument <code>$src</code> can be passed in this array, with key: <code>src</code> или <code>url</code> или <code>link</code> или <code>img</code>:
<pre><code> echo kama_thumb_img( array(
 'src' => 'http://yousite.com/IMAGE_URL.jpg',
 'w' => 150,
 'h' => 100,
 ) );
</code></pre>
</li>
</ul>
<h3>Notes</h3>
<ol>
<li>
You can pass <code>$args</code> as string or array:
<pre><code> // string
 kama_thumb_img('w=200 &h=100 &alt=IMG NAME &class=aligncenter', 'IMG_URL');

 // array
 kama_thumb_img( array(
 'width' => 200,
 'height' => 150,
 'class' => 'alignleft'
 'src' => ''
 ) );
</code></pre>
</li>
<li>
You can set only one side: <code>width</code> | <code>height</code>, then other side became proportional.
</li>
<li><code>src</code> parameter or second function argument is for cases when you need create thumb from any image not image of WordPress post.</li>
<li>
For test is there image for post, use this code:
<pre><code> if( ! kama_thumb_img('w=150&h=150&no_stub') )
 echo 'NO img';
</code></pre>
</li>
</ol>
<h3>Examples</h3>
<h4>#1 Get Thumb</h4>
In the loop where you need the thumb 150х100:
<pre><code><?php echo kama_thumb_img('w=150 &h=100 &class=alignleft myimg'); ?>
</code></pre>
Result:
<pre><code><img src='thumbnail_URL' alt='' class='alignleft myimg' width='150' height='100'>
</code></pre>
<h4>#2 Not show stub image</h4>
<pre><code><?php echo kama_thumb_img('w=150 &h=100 &no_stub'); ?>
</code></pre>
<h4>#3 Get just thumb URL</h4>
<pre><code><?php echo kama_thumb_src('w=100&h=80'); ?>
</code></pre>
Result: <code>/wp-content/cache/thumb/ec799941f_100x80.png</code>
This url you can use like:
<pre><code><img src='<?php echo kama_thumb_src('w=100 &h=80 &q=75'); ?>' alt=''>
</code></pre>
<h4>#4 <code>kama_thumb_a_img()</code> function</h4>
<pre><code><?php echo kama_thumb_a_img('w=150 &h=100 &class=alignleft myimg &q=75'); ?>
</code></pre>
Result:
<pre><code><a href='ORIGINAL_URL'><img src='thumbnail_URL' alt='' class='alignleft myimg' width='150' height='100'></a>
</code></pre>
<h4>#5 Thumb of any image URL</h4>
Pass arguments as array:
<pre><code><?php
 echo kama_thumb_img( array(
 'src' => 'http://yousite.com/IMAGE_URL.jpg',
 'w' => 150,
 'h' => 100,
 ) );
?>
</code></pre>
Pass arguments as string:
<pre><code><?php
 echo kama_thumb_img('w=150 &h=200 ', 'http://yousite.com/IMAGE_URL.jpg');
?>
</code></pre>
When parameters passes as string and “src” parameter has additional query args (“src=$src &w=200” where $src = http://site.com/img.jpg?foo&foo2=foo3) it might be confuse. That’s why “src” parameter must passes as second function argument, when parameters passes as string (not array).
<h4>#6 Parameter post_id</h4>
Get thumb of post ID=50:
<pre><code><?php echo kama_thumb_img("w=150 &h=100 &post_id=50"); ?>
</code></pre>
<h3>I don’t need plugin</h3>
This plugin can be easily used not as a plugin, but as a simple php file.
If you are themes developer, and need all it functionality, but you need to install the plugin as the part of your theme, this short instruction for you:
<ol>
<li>Create folder in your theme, let it be ‘thumbmaker’ – it is for convenience.</li>
<li>Download the plugin and copy the files: <code>class.Kama_Make_Thumb.php</code> and <code>no_photo.jpg</code> to the folder you just create.</li>
<li>Include <code>class.Kama_Make_Thumb.php</code> file into theme <code>functions.php</code>, like this: 
require ‘thumbmaker/class.Kama_Make_Thumb.php’;</li>
<li>Bingo! Use functions: <code>kama_thumb_*()</code> in your theme code.</li>
<li>If necessary, open <code>class.Kama_Make_Thumb.php</code> and edit options (at the top of the file): cache folder URL/PATH, custom field name etc.</li>
</ol>
<ul>
<li>Conditions of Use – mention of this plugin in describing of your theme.</li>
</ul>

Kama Thumbnail

Great plugin! Allows you to save space on hosting and speeds up the site. The author quickly reacts and modifies the plugin. Thank you!

Must have

Попробовал на одном огромном портале с несколькими миллионами картинок - результта превзошел все мои ожидания.

Количество фоток на сервере стало заметно меньше (а размеров у нас очень много) и делать руками приходится не так много работы.

Спасибо!

Пожалуй, лучший плагин для создания тумбочек у постов

Creates post thumbnails on fly and cache the result. Auto-create of post thumbnails based on: WP post thumbnail OR first img in post content OR attach …

Mizuho Ogino

By uploading a PDF attachment, this plugin convert the cover page to jpeg and attach it as a post thumbnail file. It also allows displaying a thumbnail icon and inserting PDF link with a cover image into the editor.
<h4>Available only for WordPress 4.0+, also only on the server which ImageMagick and GhostScript are installed.</h4>
This plugin hooks to the media editor and generates the first page image of PDF by using ImageMagick with GhostScript. It requires no setup, just activate the plugin via the admin install page. Allow to set a PDF as an image.
<h4>How it works</h4>
This Plugin replaces and extends the following features.
<ul>
<li>Generate cover image of PDF by using ImageMagick. Generated Image has different size variations and is attached to PDF.</li>
<li>Register Generated Image as Featured Image (post-thumbnail) of PDF.</li>
<li>Display Generated Image as icon instead of Mime-type Icon in Admin Page.</li>
<li>Hide Generated Image file itself in Media Library. (v1.2 or later)</li>
<li>Replace link text with JPG when inserting PDF to Text Editor.</li>
<li>Delete Generated Image when deleting PDF from Media Library.</li>
<li>Allow to manage and output Generated Image and PDF on manually in template file. (see Other Notes.)</li>
<li>Allow to set PDF as Featured Image and to use functions in the same way as image file. (v1.2 or later, see Other Notes.)</li>
<li>Allow to control maximum size of Generated Image and other default settings in Plugin Page. (v1.3.4 or later)</li>
</ul>
<h4>Generated Items</h4>
A generated image file is registered as post children of a PDF file and it has different size variations. Files build a tree like below.
<ul>
<li>my-file.pdf (Your PDF)
<ul>
<li>my-file-pdf.jpg (Generated Cover Image of Your PDF)
<ul>
<li>my-file-pdf-1024×768.jpg (Large Size)</li>
<li>my-file-pdf-300×225.jpg (Medium Size)</li>
<li>my-file-pdf-150×150.jpg (Thumbnail size)</li>
<li>…(And Your Custom File Sizes)</li>
</ul>
</li>
</ul>
</li>
</ul>
<h4>Insert HTML into the editor</h4>
Select a PDF file in the Media Uploader and insert it into the the editor. An output HTML is automatically rewritten like below.
<pre><code><a class="link-to-pdf" title="dummy-pdf" href="http://exmaple.com/wp-content/uploads/2015/01/dummy-pdf.pdf" target="_blank"><img width="227" height="320" class="size-medium wp-image-9999 thumb-of-pdf" src="http://exmaple.com/wp-content/uploads/2015/01/dummy-pdf-pdf-227x320.jpg" alt="thumbnail-of-dummy-pdf" /></a>
</code></pre>
*If you are using a document viewer plugin (like GDE) and want insert html which is made by it, select “Default (Title)” of “media” selector.
<h4>Get thumbnail in template file</h4>
A generated image ID is stored in [‘_thumbnail_id’] custom field of a PDF attachment post. An image ID is exportable by using get_post_thumbnail_id($your_pdf_id) or get_post_meta($your_pdf_id, ‘_thumbnail_id’, true) functions in a template file.
<pre><code>$pdf_id = 'your PDF file ID';
if ( $thumbnail_id = get_post_thumbnail_id( $pdf_id ) ) {
echo '<a class="pdf-link image-link" href="'.wp_get_attachment_url( $pdf_id ).'" title="'.esc_attr( get_the_title( $pdf_id ) ).'" target="_blank">'.wp_get_attachment_image ( $thumbnail_id, 'medium' ).'</a>';
}
</code></pre>
Or more simply, you can call images and link to PDF files by wp_get_attachment_image($your_pdf_id, $size) and wp_get_attachment_link($your_pdf_id, $size) functions. (v1.2 or later) *If the plugin is deactivated, this function just will return empty.
<pre><code>$pdf_id = 'your PDF file ID';
echo wp_get_attachment_image ( $pdf_id, 'medium' );
echo wp_get_attachment_link ( $pdf_id, 'medium' );
</code></pre>
If you call all PDFs that are attached to the post. You can get them by get_posts function.
Examples. 
Dynamically get PDFs that are attached to the post.
<pre><code><?php
$pdfs = get_posts( 'posts_per_page=-1&post_type=attachment&post_mime_type=application/pdf&post_parent='.$post->ID );
if( $pdfs ): foreach( $pdfs as $pdf ):
 $thumbnail_id = get_post_thumbnail_id( $pdf->ID );
 if( $thumbnail_id ):
 echo '<li>';
 echo '<a href="'wp_get_attachment_url( $pdf->ID )'" class="link-to-pdf">';
 echo wp_get_attachment_image ( $thumbnail_id, 'medium' );
 echo '</a>';
 echo '</li>';
 endif;
endforeach; endif;
?>
</code></pre>
<h4>Set PDF thumbnail as Featured Image</h4>
The plugin support you to set PDF as Featured Image. (v1.2 or later) 
Strictly explaining, when you set a PDF as Featured Image, the plugin automatically set the thumbnail which is registered with this PDF. 
You can call thumbnail by using get_the_post_thumbnail function.
<pre><code>echo get_the_post_thumbnail ( $post->ID, 'medium' );
</code></pre>
May you want pdf file from the post thumbnail.
<pre><code>$thumb_id = get_post_thumbnail_id ( $post->ID );
$pdf_id = get_post( $thumb_id )->post_parent;
if ( $pdf_id && get_post_mime_type ( $pdf_id ) === 'application/pdf' ){
 $pdf = get_post($pdf_id);
 echo '<a class="link-to-pdf" href="'.wp_get_attachment_url($pdf_id).'" title="'.esc_html($pdf->post_title).'" target="_blank">'.get_the_post_thumbnail().'</a>'."\n";
}
</code></pre>
<h4>Display attachment data with in caption</h4>
The plugin allows you to insert [caption] short-code into the post content area as when insert an image. If you want to display attachment title, description, file type, file size and so on, use img_caption_shortcode filter in your functions.php. 
Here’s an example code… 
 function add_attachment_data_in_caption( $empty, $attr, $content ) { 
 $attr = shortcode_atts( array( ‘id’=>”, ‘align’=>’alignnone’, ‘width’=>”, ‘caption’=>” ), $attr ); 
 if ( 1 > (int) $attr[‘width’] || empty( $attr[‘caption’] ) ) return ”; 
 if ( $attr[‘id’] ) { 
 $attr[‘id’] = ‘id=”‘ . esc_attr( $attr[‘id’] ) . ‘” ‘; 
 $attachment_id = explode(‘_’, $attr[‘id’]); 
 $attachment_id = $attachment_id[1];// get attachment id 
 if( get_post_mime_type ( $attachment_id ) === ‘application/pdf’ ){ 
 $attachment = get_post( $attachment_id ); 
 $bytes = filesize( get_attached_file( $attachment->ID ) ); 
 if ($bytes >= 1073741824) $bytes = number_format($bytes / 1073741824, 2). ‘ GB’; 
 elseif ($bytes >= 1048576) $bytes = number_format($bytes / 1048576, 2). ‘ MB’; 
 elseif ($bytes >= 1024) $bytes = number_format($bytes / 1024, 2). ‘ KB’; 
 elseif ($bytes > 1) $bytes = $bytes. ‘ bytes’; 
 elseif ($bytes == 1) $bytes = $bytes. ‘ byte’; 
 else $bytes = ‘0 bytes’; 
 $attr[‘caption’] = 
 ‘title : ‘ .$attachment->post_title. ‘ ‘ . // title 
 ‘caption : ‘ .$attr[‘caption’]. ‘ ‘ .// caption 
 ‘size : ‘ .$bytes. ‘ ‘ . // file size 
 ‘filetype : ‘ .get_post_mime_type ( $attachment_id ). ‘ ‘ . // file type 
 ‘description : ‘ .$attachment->post_content. ‘ ‘; // description 
 } 
 }
<pre><code> return 
 '<div ' .$attr['id']. 'class="wp-caption ' .esc_attr( $attr['align'] ). '" style="max-width: ' .( 10 + (int) $attr['width'] ). 'px;">' .
 do_shortcode( $content ). '' .$attr['caption']. '' .
 '</div>';
}
add_filter('img_caption_shortcode', 'add_attachment_data_in_caption', 10, 3);
</code></pre>
<h4>Generate thumbnails of all PDFs in the media library</h4>
You can generate thumbnails of any already-uploaded PDFs. 
Activate the plugin and Click “Generate Thumbnails Now” link in “settings”. (v1.3.3 or later)
<h4>Change attachment link attributes</h4>
<pre><code>function pigen_filter_attachment_link ( $html, $attach_id, $attach_url, $attach_output ){
 $attach_title = get_the_title( $attach_id );
 $html = '<a class="link-to-pdf" href="'.$attach_url.'" rel="attachment wp-att-' .esc_attr($attach_id). '" title="'.esc_attr( $attach_title ).'" target="_blank">' .$attach_output. '</a>';
 return $html;
};
add_filter( 'pigen_filter_attachment_link', 'pigen_filter_attachment_link', 10, 4 );
</code></pre>
<h4>Change thumbnail attributes</h4>
<pre><code>function pigen_filter_attachment_output ( $attach_output, $thumbnail_id, $thumbnail, $size, $align ){
 $attach_output = '<img src="'. $thumbnail[0] .'" alt="'.get_post_meta( $thumbnail_id, '_wp_attachment_image_alt', true ).'" width="'. $thumbnail[1] .'" height="'. $thumbnail[2] .'" class="'.( $align ? 'align' .$align. ' ' : '' ). 'size-' .esc_attr( $size ). ' wp-image-'.$thumbnail_id.'" />';
 return $attach_output;
};
add_filter( 'pigen_filter_attachment_output', 'pigen_filter_attachment_output', 10, 5 );
</code></pre>
<h4>Modify imageMagick’s Settings</h4>
Filters allow you to add your own modify imageMagick’s behaviour by hooking.
Sample usage for imageMagick user.
<pre><code>function pigen_filter_convert_file_basename( $file_basename ){
 $file_basename = str_replace( '.jpg', '.png', $file_basename );
 return $file_basename;
};
add_filter( 'pigen_filter_convert_file_basename', 'pigen_filter_convert_file_basename' );

function pigen_filter_convert_imageMagick( $imageMagick, $before_name, $after_name, $max_width, $max_height ){
 $imageMagick = "convert -density 150 -quality 80 -background black -flatten {$max_width}x{$max_height} {$before_name} {$after_name}";
 return $imageMagick;
};
add_filter( 'pigen_filter_convert_imageMagick', 'pigen_filter_convert_imageMagick', 10, 5 );
</code></pre>
Sample usage for imagick extension user.
<pre><code>function pigen_filter_convert_file_basename( $file_basename ){
 $file_basename = str_replace( '.jpg', '.png', $file_basename );
 return $file_basename;
};
add_filter( 'pigen_filter_convert_file_basename', 'pigen_filter_convert_file_basename' );

function pigen_filter_convert_imagick( $imagick ){
 $imagick->setImageBackgroundColor( 'black' );
 $imagick->setCompressionQuality( 80 );
 $imagick->setImageFormat( 'png' );
return $imagick;
};
add_filter( 'pigen_filter_convert_imagick', 'pigen_filter_convert_imagick' );
</code></pre>
<h4>Automatically save image/PDF as featured image</h4>
Automatically set PDF thumbnail as featured image.
<pre><code>function save_pdf_thumb_as_featuredimage ( $post_id ) { 
 if ( wp_is_post_revision( $post_id ) ) return; 
 if ( get_post_type( $post_id ) !== 'post' ) return; // set your post type
 if ( get_post_meta( $post_id, '_thumbnail_id', true ) ) return; // post already has featured image
 $attaches = get_posts ( 'post_parent='.$post_id.'&numberposts=-1&post_type=attachment&post_mime_type=application/pdf&orderby=menu_order&order=ASC' );
 if ( $attaches ): foreach( $attaches as $attach ):
 if ( $thumb_id = get_post_meta( $attach->ID, '_thumbnail_id', true ) ){ // if pdf has thumbnail
 update_post_meta( $post_id, '_thumbnail_id', $thumb_id );
 break;
 }
 endforeach; endif;
}
add_action( 'save_post', 'save_pdf_thumb_as_featuredimage' );
</code></pre>
Automatically set first image/PDF as featured image.
<pre><code>function save_thumbnail_as_featuredimage ( $post_id ) { 
 if ( wp_is_post_revision( $post_id ) ) return;
 if ( get_post_type( $post_id ) !== 'post' ) return; // set your post type
 if ( get_post_meta( $post_id, '_thumbnail_id', true ) ) return; // post already has featured image
 $args = array(
 'post_parent' => $post_id,
 'post_type' => 'attachment',
 'numberposts' => -1,
 'post_status' => null,
 'orderby' => 'menu_order date',
 'order' => 'ASC ASC'
 );
 $attaches = get_posts($args);
 if ( $attaches ): foreach( $attaches as $attach ):
 if ( $attach->post_mime_type == 'application/pdf' ){
 if ( $thumb_id = get_post_meta( $attach->ID, '_thumbnail_id', true ) ){ // if pdf has thumbnail
 update_post_meta( $post_id, '_thumbnail_id', $thumb_id );
 break;
 }
 } elseif ( preg_match("/^image\//", $attach->post_mime_type ) ) {
 update_post_meta( $post_id, '_thumbnail_id', $attach->ID );
 break;
 }
 endforeach; endif;
}
add_action( 'save_post', 'save_thumbnail_as_featuredimage' );
</code></pre>

PDF Image Generator

Also ties in really nicely with the media uploader, the image is set as the 'icon' field of the attachment, as one would want. PS The feature for generating images for existing pdfs is at the bottom of the settings - scroll down to see (unlike me the first time)!

Super stuff. Works perfectly.

Very impressed with how quick and easy it was to get up and running with the generated pdf views.

Great Little Plugin

Generate automatically cover image of PDF by using ImageMagick. Allow user to insert PDF link with thumbnail into editor and set as Featured Image.

Kama Thumbnail vs PDF Image Generator