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I have just changed the theme on my blog, and because of a small page width, it breaks the layout. Most of my earlier images (attached in posts) are around 600px in width, and now I need to resize all of them them proportionately to 450px. How do I resize them all at one shot? Is there a plugin for this?
P.S.: Writing a CSS rule is a good option, and I've already done that. But I figure resizing the images would also knock off the download overhead for each page!
I asked a similar but broader question, and I still need to research and write a complete answer. In the meantime here are some pointers that might help you:
I wrote a set of plugins that resizes all images to the size used in the editor. It works by converting <img src="image.jpg" width="200" height="400"/> to <img src="image-200x400.jpg" width="200" height="400"/> (Resize img tags) and catching and generating those missing intermediate sizes on request (On-Demand Resizer). You should be able to do the first part in bulk, and then let the second plugin handle the new images. It also works with partial information: image-200x.jpg will return a proportionally-resized image 200 pixels wide.
Regenerate Thumbnails indeed re-creates images at different sizes, but I don't think it also updates your post content to refer to these images? Even worse, if it deletes the old intermediate sizes, your post will still reference the now non-existing image-600x400.jpg instead of image-450x300.jpg.
Log in to your server and go to the root directory of your wordpress. Then execute:
cd wp-content/uploads/;
for img in `find . -name *.jpg -printf '%p\n'`
do
mogrify -resize "450>x" $img;
done
This will resize every JPG in your upload folder (and all subfolders!) that are wider than 450px to this width proportionally. If you have PNG, GIF, ... just rerun with the respective file ending.
I assume that you use the standard upload folder (adapt first line otherwise) and that your server has imagemagick installed.
No warranty, of course.
Try the plugin 'Regenerate Thumbnails', it does just what you're looking for.
http://www.viper007bond.com/wordpress-plugins/regenerate-thumbnails/
if ( defined( 'WP_CLI' ) && WP_CLI ) {
class RegenThumbs extends WP_CLI_Command
{
var $errors = false;
var $unique_size_name = 'past_favourites';
var $unique_size = 170;
public function __construct()
{
global $wpdb;
if ( !$images = $wpdb->get_results( "SELECT ID FROM $wpdb->posts WHERE post_type = 'attachment' AND post_mime_type LIKE 'image/%' ORDER BY ID asc" ) ) {
WP_CLI::error( "Unable to find any images. Are you sure some exist?" );
return;
}
WP_CLI::line( 'Found ' . count( $images ) . ' pictures to regenerate!' );
foreach ( $images as $image )
$this->process( $image->ID );
if ( $this->errors )
WP_CLI::error( 'Finished regenerating images - however, there were some errors throughout.' );
else
WP_CLI::success( 'Finished - without any errors either!' );
}
function process( $id=false )
{
if( ! $id )
return;
$image = get_post( $id );
if ( !$image || 'attachment' != $image->post_type || 'image/' != substr( $image->post_mime_type, 0, 6 ) ) {
$this->errors = true;
WP_CLI::line( "FAILED: {$image->post_title} - invalid image ID" );
return;
}
$meta_data = wp_get_attachment_metadata( $image->ID );
if( isset( $meta_data['sizes'][ $this->unique_size_name ] ) && $meta_data['sizes'][ $this->unique_size_name ]['width'] == $this->unique_size )
{
WP_CLI::line( "SKIPPED: $image->ID - There is an image called " . $this->unique_size_name );
return;
}
$fullsizepath = str_replace( array(
'/home/username/public_html/',
'/home/17196/domains/domain.com/html/',
'/nfs/c02/h07/mnt/17196/domains/domain.com/html/',
'/mnt/gs02/herd04/17196/domains/domain.com/html/',
'/nfs/c02/h04/mnt/17196/domains/domain.com/html/'
),
'/srv/www/domain.com/current/',
get_attached_file( $image->ID )
);
if ( false === $fullsizepath || !file_exists( $fullsizepath ) ) {
$this->errors = true;
WP_CLI::line( "FAILED: {$image->post_title} - Can't find it $fullsizepath" );
return;
}
// 5 minutes per image should be PLENTY
@set_time_limit( 900 );
$array_path = explode( DIRECTORY_SEPARATOR, $fullsizepath );
$array_file = explode( '.', $array_path[ count( $array_path ) - 1 ] );
$imageFormat = $array_file[ count( $array_file ) - 1 ];
unset( $array_path[ count( $array_path ) - 1 ] );
unset( $array_file[ count( $array_file ) - 1 ] );
$imagePath = implode( DIRECTORY_SEPARATOR, $array_path ) . DIRECTORY_SEPARATOR . implode( '.', $array_file );
$dirPath = explode( DIRECTORY_SEPARATOR, $imagePath );
$imageName = sprintf( "%s-", $dirPath[ count( $dirPath ) - 1 ] );
unset( $dirPath[ count( $dirPath ) - 1 ] );
$dirPath = sprintf( "%s%s", implode( DIRECTORY_SEPARATOR, $dirPath ), DIRECTORY_SEPARATOR );
// Read and delete files
$dir = opendir( $dirPath );
$files = array();
while ( $file = readdir( $dir ) ) {
if ( !( strrpos( $file, $imageName ) === false ) ) {
$thumbnail = explode( $imageName, $file );
if ( $thumbnail[ 0 ] == "" ) {
$thumbnailFormat = substr( $thumbnail[ 1 ], -4 );
$thumbnail = substr( $thumbnail[ 1 ], 0, strlen( $thumbnail[ 1 ] ) - 4 );
$thumbnail = explode( 'x', $thumbnail );
if ( count( $thumbnail ) == 2 ) {
if ( is_numeric( $thumbnail[ 0 ] ) && is_numeric( $thumbnail[ 1 ] ) ) {
WP_CLI::line( "Thumbnail: {$thumbnail[0]} x {$thumbnail[1]} was deleted." );
@unlink( $dirPath . $imageName . $thumbnail[ 0 ] . 'x' . $thumbnail[ 1 ] . $thumbnailFormat );
}
}
}
}
}
$metadata = wp_generate_attachment_metadata( $image->ID, $fullsizepath );
if ( is_wp_error( $metadata ) ) {
WP_CLI::line( $metadata->get_error_message() );
return;
}
if ( empty( $metadata ) ) {
$this->errors = true;
WP_CLI::line( 'Unknown failure reason.' );
return;
}
wp_update_attachment_metadata( $image->ID, $metadata );
WP_CLI::line( esc_html( get_the_title( $image->ID ) ) . " (ID {$image->ID}): All thumbnails were successfully regenerated in " . timer_stop() . " seconds " );
}
}
WP_CLI::addCommand( 'regen_thumbs', 'RegenThumbs' );
}
Sample wordpress theme : image
