Adds image shortcode with caption to editor.

Builds the Caption shortcode output.

Retrieves the URL to the includes directory.

Determines if SSL is used.

Displays advanced link options form fields.

Displays link categories form fields.

Displays form fields for changing link target.

Displays XFN form fields.

Returns a listing of all files in the specified folder and all subdirectories up to 100 levels deep.

Handles a side-loaded file in the same way as an uploaded file is handled by media_handle_upload().