Default Featured Image

About this plugin

Questions

My chosen featured image doesn’t show, why isn’t it working?

This plugin works out of the box for most cases, but not always. If it doesn’t work you can try the following things.

• Switch themes. Most of the time the theme does something weird.
• Are you using the Core WordPress functions to get the image? (see the FAQ below this one).
• Do normal feature images work?
• Might it be hidden via css? DFI images have an extra default-featured-img class added to them.

Still having problems? I want to know if it fails, so contact me

Which functions can I use to display the featured image?

There are no new functions, all core WordPress functions can be used.

• the_post_thumbnail / get_the_post_thumbnail Display the image.
• the_post_thumbnail_url / get_the_post_thumbnail_url Get the url.
• has_post_thumbnail If a DFI is set it will always return true.
• get_post_thumbnail_id will return the ID set on the post or the DFI.

Can I set a different image for a custom post type?

Yes, the following code will set a different image.

add_filter( 'dfi_thumbnail_id', 'dfi_posttype_book', 10, 2 );
function dfi_posttype_book( $dfi_id, $post_id ) {
    $post = get_post( $post_id );
    if ( 'book' === $post->post_type ) {
        return 31; // the image id for the book post type.
    }

    return $dfi_id; // the original featured image id.
}

Can I set different images per category?

Yes, the following snippet will set different images based on the category.

add_filter( 'dfi_thumbnail_id', 'dfi_category', 10, 2 );
function dfi_category( $dfi_id, $post_id ) {
    // Set a different image for posts that have the 'cats' category set.
    // This will trigger first, if multiple categories have been set.
    if ( has_category( 'cats', $post_id ) ) {
        return 7; // cats img id.
    }
    // Set a different image for posts that have the 'cats' category set.
    if ( has_category( 'dogs', $post_id ) ) {
        return 8; // dogs img id.
    }

    return $dfi_id; // the original featured image id.
}

Can I change the HTML of the default featured image?

When a Default Featured Image is used it will already add an extra class default-featured-img.
This can be used for styling.

If you need more you can change the whole HTML with the filter dfi_thumbnail_html.

add_filter( 'dfi_thumbnail_html', 'dfi_add_class', 10, 5 );
function dfi_add_class( $html, $post_id, $default_thumbnail_id, $size, $attr ) {
    // Add a class to the existing class list.
    $attr['class'] .= ' my-class';

    return wp_get_attachment_image( $default_thumbnail_id, $size, false, $attr );
}

Can I exclude one page from having a Default Featured Image?

The following code will exclude the post/page with ID 23.

add_filter( 'dfi_thumbnail_id', 'dfi_skip_page', 10, 2 );
function dfi_skip_page( $dfi_id, $post_id ) {
    if ( $post_id == 23 ) {
        return 0; // invalid id.
    }

    return $dfi_id; // the original featured image id.
}