Citing a photo from an Ancestry user account

History-Hunter, I'm puzzled. Why italics for the identity of the photo? In both EE and CMOS, italics are used for the title of a standalone publication, not for an item that is just one part of a publication. (EE 2.22) A photo at Ancestry is just one item that is just one part of the much bigger publication, the Ancestry website.

History-Hunter, I’ll take each issue separately in this response, following basically the order in which you raise the issues:

CMOS 14.235

This section treats art that is issued/produced/published as a standalone work—as opposed to being published as part of, say, an “art book.” Citing Salvador Dali's The Persistence of Memory, a standalone piece of art, is  handled in the same way as citing a map that is published alone rather than being part of, say, an atlas.

Citing photographs at Ancestry

A photograph that someone has attached to a person-profile, in a “tree” compiled at a website, is not a standalone publication. It’s handled the same way we would handle a photograph in someone’s chapter in a book that has a different author for every chapter. It’s just one small part of the much-bigger whole. We identify both the individual part and the whole.

Basic principle involved

Italics signify a standalone publication is a uniform principle across almost all citation manuals—the notable exception being Associated Press style, rooted in an era when newspaper type was set by hand and the use of italics complicated the typesetting process.

Identifying websites by URL only

Re: CMOS’ advice to add a URL (as opposed to actually identifying a website), you’ve pointed to one of the basic differences between CMOS and EE:

• CMOS, being a manual for editors and publishers, recommends the minimum amount of identification necessary to relocate a source.
• Evidence Style citations are designed to help researchers record all information they might need to evaluate the validity of a source and the evidence drawn from it—not just where to go to find the source again. Therefore EE recommends fully identifying a website, the provider, and other individuals or elements essential to determining the credibility of the material.

EE’s origin

You also write:

“While I understand from other postings that you consider the CMOS and EE-Style to be two different standards, I also understand that EE-style has its origins in the CMOS standard.” 

Clarification is definitely needed for that second 'understanding' of yours. Evidence Style, as set forth in EE, has “common roots” with CMOS. Long before either of us existed, there was Turabian (also from the University of Chicago Press), a style guide created for graduate students. Before EE there was also Lackey, designed for genealogists. The three developed as follows:

• CMOS built upon Turabian to create a more-comprehensive guide for editors and publishers, not just students. Like Turabian, CMOS embraces Humanities Style, Scientific Style, and Legal Style citations, as well as other style issues rooted in grammar, punctuation, spelling, and formatting. 
• Lackey built upon Turabian and CMOS to focus specifically on genealogical sources, but with idiosyncratic formats that had no basic pattern from one source type to another—making it difficult for software companies to create automated templates.
• EE built upon its predecessors to (a) create a more-comprehensive guide to evidence-based citation and analysis, specifically for those who do humanities-based research and writing; and to (b) develop a set of basic formats that could be adapted to all types of materials.

For basic publications, CMOS, Lackey, and EE adhere to the same structure set forth in Turabian. (MLA, APA, BlueBook, ALWD, McGill, and others do not.)

Once we move beyond the realm of basic publications into that of complex historical resources of widely varying reliability—whether in original form or replicated online—EE and CMOS differ radically in their recommendations. That difference is the core of EE, since ten of its twelve source-focused chapters treat unpublished works.

As indicated above, CMOS’s recommendations are designed for editors and publishers who need to meet minimal standards while conserving space. EE is designed for historical researchers and writers who need to capture all information essential to the evaluation of a source and its reliability. That is a significant difference in the basic standards, as well as the fundamental philosophy that underpins them.

Recommended citation in this specific case

I’ll treat this separately, so it will not get lost amid the discussion of principles and philosophies.

History-Hunter, to return the conversation back to your initial question of how to cite a photograph at Ancestry, you write:

Per EE section 2,22, I'd judge this to fall under the category of being a "Named Part of a Published Book". If I am correct, the only necessary change is to remove the italics from the title and place the title in double quotation marks.”

Your original citation was this:

Iveybet [pseud.], account owner, Hazel Ida Strom & Michael Brophy celebrating 50th Anniversary with children; digital image, sRGB IEC61966-2.1, 480x308 pixels, imaged at Ancestry (http://www.Ancestry.ca : downloaded 19 May 2022). Hazel and Michael are known to have married in 1935, leading to dating the photo as being ca. 1985.

Yes, EE would treat this as a “named part of a published book,” but the photograph itself is not the equivalent of a titled chapter in a published book. It's the equivalent of a chapter author putting a photograph or a map or a table, etc., on p. xxx of their named chapter. The citation needs to identify the chapter or tree that Iveybet created, not just someone photograph that was added to her creation.

Put another way: How do we find that particular image at Ancestry?  If you simply put quotation marks around the photograph’s title, as named by Iveybet, we can’t just type in that phrase in the “search collections” box, as we would with a named collection at Ancestry, and get a hit. That individual photograph and the name given to it by the person who uploaded it, is not a named collection at Ancestry. 

EE would handle the citation this way, using Ancestry’s current architecture:

     1. Iveybet, “Name of Iveybet’s Tree,” user-contributed tree, Ancestry (exact URL for the page to which this tree is attached : download date), “Hazel Ida Strom,” profile [or “facts” page or “gallery” or wherever it is accessed], photo titled “Hazel Ida Strom & Michael Brophy celebrating 50th Anniversary with children.”

To include the technical specs for the photo, EE would add those details to a second layer:

     1. Iveybet, “Name of Iveybet’s Tree,” user-contributed tree, Ancestry (exact URL for the page to which this tree is attached : download date), “Hazel Ida Strom” profile, photo titled “Hazel Ida Strom & Michael Brophy celebrating 50th Anniversary with children”; the digital image, sRGB IEC61966-2.1 format, is 480x308 pixels.

History-Hunter, yes, indeed.  EE's QuickSheet: Citing Ancestry Databases & Images has an example for that. Following it in your case would generate this:

"Public Member Photos & Scanned Documents," Ancestry ([full URL here, not just to the collection level] : downloaded 21 May 2022), “Hazel Ida Strom & Michael Brophy celebrating 50th Anniversary with children," photo, posted [whatever date] by "Iveybet."

I started to include this as an option in the earlier discussion, but the discussion was so lengthy that I decided against it. Thanks for bringing it up.