Hi Jim-
I did a bit of a search on the name Treganowan, and I often just google it or try https://www.langdonroad.com Did not find him/her on Langdon Rd so looked on Ancestry. I did learn something about city directories on Ancestry- when one is puilled up, you can click on the city or state in the top menu bar, above the page, and a drop down will show which additional directories Ancestry has. I did not find that name as a photographer in 1916 but in 1902, there was a Thomas Treganowan with “pictures” after his name suggesting his occupation. He worked at 437 Penn av and home was 1340 Lincoln Ave.One of the censuses that came up on the Ancestry search listed a Thomas T as a “mat cutter” which may be how he got into the business. I also found a ref on Google about a Treganonwan Art Co. in 1903, and a Thomas T who patented a incinerator in both the US and Canada- may take a while to figure out if there were multiple Thomas T’s, and he may not even be the correct one. Can you guess the time period of the photo(s) as a starting place for your research? You might check some of the other Pittsburgh City Directories either just before or after 1902. Also, sometimes a photographer’s name will come up on Google as listed in one of the photography magazines for professionals, and it might mention a studio being started or sold. Please let us know if you learn any more about these photographers, and thanks for reading.