Re: Zachary Taylor Davidson
Hi - I'm a volunteer.
You've done a lot of research on Zachary and family. When you ask "for information" it is difficult to guess what specific information to seek, what it is you do not already know. A volunteer researcher will begin by posting records for Zachary, because in doing family history research as you know, one works from record to record, the information builds, and leads to more. In this case, this process would be repeating what you've seemingly already accomplished, so....
As for a photograph, that is most likely to be found in the collection of a descendant (or descendant of a near family member). Perhaps you might add descendant names, their spouses, and their children and locations. These additions might draw somebody out there in the land of the internet who is doing a Google Search, parsing with another name but maybe not Zachary's name.
Hope this helps a teeny bit.