Display post image in a size defined by add_image_size()

Question

As I already used the featured image for something else, I want to add another image and display it in one of the sizes defined in my functions.php with add_image_size().

I know how to do that with a featured image : I just have to use the_post_thumbnail() function and indicate the size I want in the parameters. But what about a post image ?

Answer 1

Try using wp_get_attachment_image() (Codex ref)?

echo wp_get_attachment_image( $attachmentid, $imagesize );

Where $attachmentid is the attachment ID, and $imagesize is the name of the image size in the add_image_size() call.

EDIT

For a custom-field stored image SRC URL, I'm not finding any way to make use of intermediate image sizes defined via add_image_size() (or even the default image sizes). Pretty much all of the related functions eventually require an attachment ID.

Answer 2

Yes, more or less. The $name parameter of add_image_size with can be called like this,

the_post_thumbnail( 'your_add_image_size_name' );

Answer 3

Within you functions.php, first define your custom thumbnail image:

add_image_size( 'custom_thumbnail', 300, 200, true );

Then use the following code to retrieve this thumbnail size:

$image_data = wp_get_attachment_image_src($attachment->ID , 'custom_thumbnail');

There is no post image, maybe you mean the post featured image? If so you can get the attachment id using this:

$thumbnail_id = get_post_meta($post->ID, '_thumbnail_id', TRUE);

then use

$image_data = wp_get_attachment_image_src($thumbnail_id , 'custom_thumbnail');

Or get all post images:

$argv = array( 'post_parent' => $post->ID, 'post_type' => 'attachment', 'post_mime_type' => 'image', 'orderby' => 'menu_order' ); $attachments = get_children($argv);

Answer 4

You need to think a bit different to solve this one, at the moment I see two different approaches to the problem.

You can use some css to resize the image, just assign a class to the image based on your add_image_size preferences and set some css rules to give the desired size, not a real resize, but sometimes it's enough.

Or you can use some third party script like tinythumb to generate a real thumbnail.