A masculine Hebrew name meaning "my strength" or "strong." Two individuals are found in the Bible with this name, and little is known of either men.
1 Chronicles 6:46 indicates Amzi as a Levite man of the family of Merari. Only briefly mentioned in a geneological list of the descendants of Levi, he is of the Jewish line of priests.
The other Amzi, son of Zechariah, was the name of an ancestor to the Levite priest Adaiah (Nehemiah 11:12). By the Persian King Artaxerxes' permission, Adaiah was one of the Israelite exiles under the direction of Nehemiah who returned to Jerusalem to rebuild the city walls after Ezra had previously led a group that rebuilt the second Jewish temple.
(From International Standard Bible Encyclopedia, KJV Bible, & Blue Letter Bible)
Amzi Allen's wife was of Puertogese and French ancestry; this probably accounts for the dark coloring of many of the family.
AMzi himself had large, heavy features, particularly his wide nose and his eyebrows, and also the distinctive forehead furrows, characteristic of the Tuttle family who were among his ancestors.
I can't tell if the other photo of a middle aged man is of Amzi or not; many of the features look similar, but his face isn't as long and seems to belong to a man with a different personality; in fact, a man who looks VERY British emigrant.