The unborn babies already smiling for the camera The heartwarming image is of the unborn son of John and Charlotte Steel Were prompted to come forward after seeing image released last weekÂ Showed baby Leo Hargreaves beaming in the womb at 31 weeksÂ Scans are 4D - a highly developed form of traditional ultrasound With his head rocking backwards and laughing heartily, he looks the picture of happiness inside his mother's womb. The heartwarming image is of the unborn son of John and Charlotte Steel, from Manchester. They were prompted to come forward with it after we reported how Leo Hargreaves stunned his parents when he beamed for his 31-week scan. The heartwarming image is of the unborn son of John and Charlotte Steel, from Manchester 4D scans are increasingly popular with expectant parents to get a glimpse of how their child will look The image is a 4D scan - increasingly popular with expectant parents to get a glimpse of how their child will look.Â Rather then the grainy â€˜flatâ€™ images produced by the 2D scanners usually used by the NHS, a 4D machine stitches together pictures taken from a variety of angles to create clear three-dimensional images. 519 shares These are then recorded on video â€" the fourth dimension. As with older forms of ultra-sound, sound waves a emitted from a transducer, or probe, which is placed on the mother's abdomen and then moved to 'look at' areas in the uterus.Â These sound waves bounce back off the foetus, helping to create a 'picture' of the child on a screen.Â Last week, baby Leo Hargreaves stunned his parents when he beamed for his 31-week scan John and Charlotte Steel with the scan of their already very happy baby boyÂ 4D scans use the same frequency of sound waves as in a normal ultrasound.Â The remarkable image of Leo Hargreaves was taken from an ultrasound scan at 31 weeks. His mother Amy Cregg, 24, said of her scan: 'My partner Leighton and I were absolutely shocked - even the people who did my scan were amazed. After he was born, he was always smiling - even in his sleep.'Â