The photo is a stock image for sale through Shutterstock:
https://www.shutterstock.com/image-photo/wiscasset-waterville-farmington-railway-maine-usa-48291406If you are an ad agency, and looking for a photo of "Farmington Maine" via Shutterstock, you get this search result:
https://www.shutterstock.com/search/farmington+maine?image_type=photoSo, that is likely what happened.
That said, there was a far more egregious example of a railroad station/model train display depot museum somewhere (in the south, I think) that was using a photo of #10 at Sheepscot as part of their rack card/tourist flyer. I believe we asked them (nicely, I hope) to not use an image of our railroad to illustrate their museum.
The other, larger, issue this raises is the fact that "Wiscasset" "Waterville" and "Farmington" are (relatively) large towns in Maine, and we are often asked where our stations are in these locations. This causes a good deal of confusion to the typical visitor, and something we need to be vigilant about clarifying (until such time we do have stations in those places. :-)