Photography started being used for evidence collecting and making "mug shots" almost as soon as it was patented. when was it first used in the courtroom?

1851

Explanation:

Photography was first presented in courtroom in 1851 as evidence against a criminal case that was solved based on the photograph of a fudged document.  Later on by 1870s, the use of photography in solving court cases became a common practice. The first use of forensic photography was done by Alphonse Bertillon when he took several shots of crime scene which later helped to resolve the case.