The ball bounces to head height and de Bruyne goes for it with his foot. Richards wants to head the ball but sees the foot and changes direction slightly, de Bruyne's studs catch him on the way down as Richards is running in. The connection in the picture is a complete accident. If Richards had gone for the header and been caught by de Bruyne's boot then it may well have been a red but people on here must be pretty desperate to compare it to Bennett's foul.