How to batch resize images and change image url?

Question

I'm making a new theme for a blog that will be slightly narrower. Thus I need to resize every image and also change the image url in every post. Is there any kind of plugin handling this?

Answer 1

This plugin might help you : Regenerate Thumbnails

Just change the image dimensions in WP's Media Settings and run the plugin.

Answer 2

in function.php you can define your default thumbnail size :

// Set featured image sizes
add_theme_support( 'post-thumbnails');
set_post_thumbnail_size( 320, 320);

And then you can even define different format which you can use in your custom theme

add_image_size( 'sidebar', 75, 75, true);
add_image_size( 'gallery', 159, 159, true);

function custom_gallery(){
    global $post;
    $args = array(
    'post_type' => 'attachment',
    'post_mime_type' => 'image',
    'numberposts' => -1,
    'orderby' => 'menu_order',
    'order' => 'ASC',
    'post_parent' => $post->ID,
    'exclude'     => get_post_thumbnail_id()
    );
    $images = get_posts($args);

    foreach($images as $image){
        if($images){
            // use gallery size thumbnails
            $thumbnail_array = image_downsize( $image->ID, 'gallery' );
            $thumbnail_url = $thumbnail_array[0];
        }
    }
}

Answer 3

Wait, wait… How do you tell your SQL replace what height the thumbnail generated by wordpress is?

So far the only solution I found is to searh/replace all the filenames and get rid of the width, making it ending like picturename-100x.jpg and then either batch replace all the urls in the posts contents or by creating an .htaccess redirect to send any image like picturename-100x\d\d\d?.jpg to picturename-100.jpg

If you come up with a better solution, let me know!

Ideally, I'd like a plugin that figures out the height from the existing same-name images (disregarding 000x000.jpg) and to write the proper width-height.