The baker’s dozen The “unlucky 13″ is the reason why the thirteen loaves that bakers once supplied were never called by the number, but described as “a baker’s dozen.†The thirteenth loaf was regarded as a special bribe for the devil not to spoil the sale or the bread. Source Link:
so many ghost picture will target the number 13 , i dont know the exact reason . but i like the number very much personally
13 is the number of Judas the Apostle who betrayed Jesus . This is why it stands for evil & betrayal so unlucky is a soft word for 13 .