I wanted to be able to use the media attachment's title, description, and maybe even the permalink and image link too. I felt that a caption specific hook should be added to the media.php
file.
When I went to submit an enhancement request, it looked like someone beat me to it. Unfortunately, that was four years ago. I bumped it.
In the meantime, I published the GIC plugin to add this caption hook for me. Once the plugin is installed, you can write a filter to use more media attachment meta as your caption. With a filter, you can even add more styling or remove/hide the caption completely.
Here's an example filter that pulls in the image's title, caption, description, creates a download link, and adds some custom styles.
/**
* Custom Filter for Gallery Image Captions
*/
function my_gallery_image_caption($attachment_id, $captiontag, $selector, $itemtag) {
$id = $attachment_id;
$my_image_meta = galimgcaps_get_image_meta($id);
return "<{$captiontag} class='wp-caption-text gallery-caption' id='{$selector}-{$id}'>"
. "<strong>" . wptexturize($my_image_meta['title']) . "</strong><br><br>"
. wptexturize($my_image_meta['caption']) . "<br><br>"
. wptexturize($my_image_meta['description']) . "<br><br>"
. "<strong>Alt Text</strong>: " . $my_image_meta['alt'] . "<br><br>"
. "<a href='" . $my_image_meta['src'] . "' target='_blank'>Download Image</a>"
. "</{$captiontag}></{$itemtag}>";
}
add_filter('galimgcaps_gallery_image_caption', 'my_gallery_image_caption', 10, 4);
Check out the documentation and examples to see if this works for you. Shout if you have any questions.