The tradition of a baby picture in a dress at about a year old, goes back quite a ways. This picture is Thomas I.S. Boak, born in 1890. The photo is probably from late 1890.
The tradition continued in 1917, when these two pictures of Thomas I.S. Boak, Jr (aka Sonny) were taken in a very traditional dress. Now, over 100 years later, we are still taking these pictures in that same dress between 11 and 12 months of age. What follows are pictures from the 1940's:
The next rows are from the 1970's and 80's
Finally 21st Century Pictures