wp_get_missing_image_subsizes ( $attachment_id )
- (int) $attachment_id The image attachment post ID.
- (array) An array of the image sub-sizes that are currently defined but don't exist for this image.
- Introduced in WordPress: 5.3.0
- Deprecated in WordPress: —
Compare the existing image sub-sizes (as saved in the attachment meta)
to the currently registered image sub-sizes, and return the difference.
Registered sub-sizes that are larger than the image are skipped.