As of WordPress 3.9, WordPress generates HTML5 Galleries if HTML5 is supported in the theme:

add_theme_support( 'html5' );

Originally in my theme development I did not declare HTML5 support and I've already published a few galleries which are using the old DT / DL HTML. Now I have declared HTML5 theme support as shown above, but WordPress won't regenerate my gallery even after saving the page or publishing a new gallery.

How do I "trick" WordPress or have WordPress start generating HTML5 galleries after my theme has been activate / activated?

2 Answers 2


Try this:

add_theme_support( 'html5', array( 'gallery', 'caption' ) );

And don't forget to declare the HTML5 DOCTYPE at the very beginning of header.php with:

<!DOCTYPE html>
  • 1
    I guess I didn't read that WP 3.9 Gallery Article all the way through: "For forward compatibility reasons, the second argument with the specific parts can’t be omitted when registering support. Otherwise a theme would automatically declare its support for HTML5 features that might be added in the future, possibly breaking its visually because of it." -- Thanks!
    – Howdy_McGee
    Commented Dec 4, 2014 at 15:56

By Using

add_theme_support( $feature, $arguments ); 

Support for the gallery and caption


add_theme_support( 'html5', array('gallery', 'caption' ) );

Source: http://codex.wordpress.org/Function_Reference/add_theme_support

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