Add Hook for icon media

Good to hear from you again; thanks for the kind words and for your question.

MLA uses a standard WordPress function, wp_get_attachment_image(), to generate its thumbnail markup. There is an existing filter in that function you can hook to get the results you seek:

        /**
         * Filters the list of attachment image attributes.
         *
         * @since 2.8.0
         *
         * @param array        $attr       Attributes for the image markup.
         * @param WP_Post      $attachment Image attachment post.
         * @param string|array $size       Requested size. Image size or array of width and height values
         *                                 (in that order). Default 'thumbnail'.
         */
        $attr = apply_filters( 'wp_get_attachment_image_attributes', $attr, $attachment, $size );

I am marking this topic resolved, but if you have any problems or further questions about using the above filter to accomplish your goal, post an update and I will investigate further. Thanks for your continued interest in the plugin.

Hi David,

Thanks for your response.

There is indeed a hook in the standard function wp_get_attachment_image(), but all my pdf don’t go in this hook because in the function wp_get_attachment_image, they don’t have image src..

But, I hook into function wp_get_attachment_image_src() and I get the good result !
This is how I make, if someone is interested :

if(!function_exists('sp_change_icon_pdf_media')){
    function sp_change_icon_pdf_media($image, $attachment_id, $size, $icon){

        global $pagenow;

        if(!is_admin() && $pagenow != 'upload.php')  return $image;
        
        $mime_type = get_post_mime_type($attachment_id);
        if($mime_type == 'application/pdf'){
            // Do stuff
            $url = 'https://www.domain.com/test.jpg';
        } else $url = '';
        
        return array($url, 64, 64, $icon);
    }
    add_filter('wp_get_attachment_image_src', 'sp_change_icon_pdf_media', 10, 4);
}

Thanks again David,
Anthony

Thanks for adapting my suggestion and finding a better solution! Thanks as well for sharing your code so other users can benefit from it.