I hope you have been in touch with Rick Pitz for whatever information he may be able to find for you. Rick is an excellent source.
To address your question about finding photographs of NANCY HANKS and L.V. STANFORD, see this page from the website American Merchant Marine at war, which lists sources of photographs of World War II-era merchant ships: http://usmm.org/photosource.html.
In that list, Mr. Hultgren, the second entry, has/had a collection exclusively of Liberty ships (NANCY HANKS being a Liberty) but he is very elderly and may no longer be managing his collection. The library at the Mariners Museum in Newport News, Virginia, fourth on the list, may be helpful for either ship. I have also heard of some researchers being successful by contacting the Library of Congress’s “Ask A Librarian” service, sixth on the list, at https://www.loc.gov/rr/askalib/ and https://www.loc.gov/rr/askalib/ask-print.html.
Since your uncle was assigned to the Treasure Island Armed Guard Center, he would have been assigned to ships traveling in the Pacific Ocean. Indeed, most of the information I can find concerning NANCY HANKS indicates extensive operations in the Pacific. Therefore I will point you to another photo source, the Miramar Ship Index, located in New Zealand (http://www.miramarshipindex.nz/). Through this website one can purchase photographs of ships that called at ports in New Zealand and Australia. It is quite likely that the Miramar Ship Index may have an image of NANCY HANKS. Problem is, this is a subscription website (with the cost of purchasing any photograph being in addition to the subscription cost) and only members can search the website to see if a photograph of a given ship is in their database. But ... the site offers a seven-day free registration, easily long enough for you to determine whether a photo of NANCY HANKS is to be found and purchase it if it is available and worth it to you, then cancel your registration and pay nothing more.
From everything I can find about L.V. STANFORD, she may have operated exclusively in the Atlantic and Caribbean so the advice directly above will not be useful for that ship. You will have to use the other sources noted earlier.
Ron Carlson, Webmaster
Armed Guard / Merchant Marine website