Posted By:
Bill CornellNice site, Scott.
Many, if not most, of the T206 portraits were made from photographs taken at the Charles (Carl) Horner Studio located at 11 Winter St., Boston, MA, now the home of a bagel shop. Horner was the official photographer of baseball for a number of years at the beginning of the 20th century.
Horner's photos first appeared on cards, cabinet and otherwise, in the W600 and W601 Sporting Life and the E107 Breisch-Williams sets in 1902-03. To the best of my knowledge, the entire T204 set in 1909 is made up of Horner photos, along with many of the T205 and T206 portraits.
I don't know of one resource where these photos can be found, although I have seen some in the reserved section at the Boston Public Library. Unfortunately, the library expects you to know what you're looking for and won't make a special effort to find things...