Fashion icon Heidi Klum has amazed fans with astonishing throwback photos from one of her earliest modelling shoots. Heidi Klum poses at 19 years old, undated. She posted several swimsuit snaps. (@heidiklum/Newsflash) The 50-year-old supermodel's mum found the Polaroids in a long-forgotten box in the basement of the family home in Germany. Amazed Heidi realised they were her entry snaps for a TV modelling contest when she was just 18…