Downloads an image from the specified URL, saves it as an attachment, and optionally attaches it to a post.

Retrieves the single non-image attachment fields to edit form fields.

Displays the multi-file uploader message.

Outputs the legacy media upload form.

Handles form submissions for the legacy media uploader.

Retrieves the legacy media uploader form in an iframe.

Adds gallery form to upload iframe.

Outputs the legacy media upload header.

Displays the browser’s built-in uploader message.

Retrieves the legacy media library form in an iframe.