The main catch is consent.
See Photography for other aspects.
- The earliest medical photograph is an American daguerreotype showing the dissection of a cadaver taken by 1844 or 1845
- The earliest definite clinical photograph was of a Scottish woman with a goitre taken by Hill and Adamson in ca. 1847 
- The earliest major publication was in 1855, Berend 'Über die Benutzung der Lichtbilder für heilwissenschaftliche Zwecke’'
- The first journal 'Internationale medizinisch-photographische Monatschrift' devoted to medical photography was published in Leipzig in 1894