People used to dress up in their best clothes and dress their children up for Sunday school. Church and Sunday school images thus used to be a good reflection of dress clothes. This was as true for children as their parents. Church is no longer such a formal occasion. Men commonly still wear a sports coat and tie, but often not a suit.
Boys are much less likely to wear a sports jacket or suit.
Special days such as Easter and Christmas or events such as weddings and christenings, however, still often are occasiins for formal dress. Information on the clothing worn to church and church related activities provide some interesting information on the clothing boys wore during various historiacal periods.