High speed monitoring of the freezing process of freely suspended supercooled pure and salty water droplets is reported for the first time. Combined visual (VIS) and infrared (IR) imaging directly delivers three-dimensional and surfacetemperature information of the proceeding freezing front with up to 2000 frames per second. The freezing behavior changes gradually up to 1 M and dramatically above 1 M NaCl concentration. To capture the initial stage of nucleation molecular dynamics (MD) calculations with atomistic and femtosecond resolution have been performed and homogeneous ice nucleation in a salt solution has been successfully simulated. Combination of experimental imaging and calculations allows to unravel structural (e.g., preferred bulk or surface location of the ice nucleus and final ion distribution) and dynamical (timescales for nucleation and freezing) aspects of the freezing process in water and salt solution. While the thermodynamic consequence of added salt, i.e., lowering of the freezing point, is well known, here we elucidate the kinetic anti-freeze effect of added salt and the molecular origin of the corresponding slow-down of ice nucleation and freezing.