| attachment_url_to_postid() | Tries to convert an attachment URL into a post ID. |
| get_allowed_mime_types() | Retrieve list of allowed mime types and file extensions. |
| wp_check_filetype() | Retrieve the file type from the file name. |
| wp_get_audio_extensions() | Returns a filtered list of WP-supported audio formats. |
| wp_get_ext_types() | Retrieves the list of common file extensions and their types. |
| wp_get_video_extensions() | Returns a filtered list of WP-supported video formats. |