shortcode get thumbnail size

Question

How to get shortcode thumbnail size?

my code get shortcode thumbnail size in functions:

function thumb_medium( $atts, $content = null ) {
    return wp_get_attachment_url( get_post_thumbnail_id( $post_id, 'medium') );
//or wp_get_attachment_url( get_post_thumbnail_id( $post_id, 'large') );
//or wp_get_attachment_url( get_post_thumbnail_id( $post_id, array(100,100)) );
}
add_shortcode("get_urlthumb", "thumb_medium");

but [get_urlthumb] always echo full url thumbnail as: wp-content/uploads/2015/08/origin-image-upload.jpg

Thanks

Answer 1

I think your code is very close, try to use wp_get_attachment_image_src() instead:

function thumb_medium( $atts, $content = null ) {
    // return wp_get_attachment_url( get_post_thumbnail_id( $post_id, 'medium') );
    global $post;
    $thumb_url = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'medium' )[0];
    if ($thumb_url) {
        return $thumb_url;
    }
}
add_shortcode("get_urlthumb", "thumb_medium");

Answer 2

You can also go with aq_resize function.
There are second and third arguments are given for size, so you can give any size that's you want.
Even you can also set these size using shortcode. Check how to pass arguments to shortcode and pass using shortcode if want to fetch dynamic size for each time

function thumb_medium( $atts, $content = null ) {
    $thumb = wp_get_attachment_url( get_post_thumbnail_id( $post_id, 'full') );
    $thumb = aq_resize( $thumb, 400, 400, true ); //resize & crop img
}
add_shortcode("get_urlthumb", "thumb_medium");