It seems to me that the picture included for the person Alexander Robert Reinagle is not correct. The main source of the confusion is probably the fact that there are two composers named Alexander Robert Reinagle, one being the uncle of the other.
As Wikipedia says:
Alexander Robert Reinagle (23 April 1756 — 21 September 1809) was an English-born American composer, organist, and theater musician. He should not be confused with his nephew of the same name, Alexander Robert Reinagle (21 August 1799 — 6 April 1877),[1] also a composer and organist, who lived all his life in Britain.
So, in this case Alexander Robert Reinagle the younger is the composer of the hymn tune, but doing a reverse-search on the page image seems to indicate it is actually a portrait of Alexander Robert Reinagle the elder (like on this page, for instance). Unless someone can confirm it's actually a picture of the other Alexander Reinagle, I'd suggest it be removed to avoid misleading others.
Comments
Incorrect portrait
The portrait has been removed to avoid confusion.