import type { FieldHook } from 'payload';
/**
 * Field validation for the favicon upload: Google rejects favicons under 48×48,
 * so warn the editor at save time if the uploaded icon is too small or not
 * square. This ENFORCES the requirement instead of silently shipping a favicon
 * Google won't display.
 *
 * Attach to the favicon field's validate (or as a beforeValidate hook on the
 * Media relationship). Non-blocking by default — returns a warning string that
 * Payload surfaces; make it throw if you want a hard block.
 *
 * Note: dimensions come from the related Media doc (Payload stores width/height
 * for image uploads), so this checks the resolved upload, not the raw file.
 */
export declare const validateFaviconField: FieldHook;