Remove Extra 10px from Captions

WordPress by default adds an extra 10px to the width of the container that wraps images with captions. This is because the default styling for captions has a thin border that surrounds the entire image.

In a recent design I decided I wanted to caption images in a slightly different way and just have the caption below the image without the surrounding border like so.

Its a cat!

To remove the additional 10px just add the following code to your function.php.

function remove_caption_extra_width($width) {
   return $width - 10;
}
add_filter('img_caption_shortcode_width', 'remove_caption_extra_width');