The Frick Digital Collections are a treasure trove of images and contemporary records of artists whose work is in the Frick Collection. Mr. Frick employed fulltime curators to collect and catalog images and records not only on the artwork and artists that were in his collection, but work by those artists that he collected but did not own. He wanted a full background maintained on all the information that he could keep on the artist and their output.
The following link will open to a search function. Enter Francis Davis Millet and 61 files and images will open for review. It is also interesting to “wander” through other artists and their work in the archive, there are literally tens of thousands of art records available.