How can I modify the media upload form fields?

Question

I would like to add a line of text under the description field in the media edit form to give users more direction as to how to fill out this field. What is the best way to do this? I know how to add form fields, but can't seem to figure out how to modify existing ones.

I added

unset($form_fields['post_content']); 

but for some reason this doesn't seem to remove the default description field.

Thanks!

Answer 1

Would maybe look into do_action( 'pre-upload-ui' );.

Here is my first thoughts, please note it's not tested but should get you in the right direction.

add_action( 'pre-plupload-upload-ui', 'sd_extra_info' );

function sd_extra_info()
{
    # see wp-includes/media-template.php
    print '<pre> Some more info here </pre>';
}