How the collar is worn depends on the denomination of the clergyman, although things in the UK are changing.
The picture from LHAAP shows a minister in the Protestant denomination; priests in the Roman Catholic church would wear the "back to front" collar. In the UK, Church of England and Roman Catholic clergy wear the "back to front" collar, and increasingly ministers in the Dissenting denominations (Baptists, Methodists, United Reformed) do too, although the older ministers often prefer to stick to wearing the traditional "bands" of these denominations, i.e. like the German minister in LHAAP's picture.
