The first thing you need to nail down is which "Chicago Style" you are supposed to be following. The Chicago Manual of Style, 15th Edition (2003) offers this observation (under the heading "Legal Citations," at 17.275):
Stylebooks. Citations in predominantly legal works may follow one of three guides: The Bluebook: A Uniform System of Citation, 17th edition, published by the Harvard Law Review Association in 2000; (2) the newest style guide, the ALWD Citation Manual: A Professional System of Citation, prepared and published by the Association of Legal Writing Directors and Darby Dickerson in 2000; or (3) The University of Chicago Manual of Legal Citation, 2d edition (2000),edited by the staff of the University of Chicago Law Review... Whichever system you choose, follow it consistently throughout a work.
So if you want to follow "Chicago Style" and your work is "predominantly legal," you should consult the University of Chicago Manual of Legal Citation, not the Chicago Manual of Style, for guidance. I direct your attention, in particular, to Rule 4.2(A)(c)(2) of that style guide:
Supreme Court reporters. Supreme Court cases should be cited in the following order of priority:
1st — US reporter cite if it exists.
2d — S Ct reporter cite if it exists.
3d — WL cite if it exists.
4th — LEXIS cite if it exists.
Unfortunately, as far as I can tell, the UCMLC doesn't discuss how to cite a syllabus to a Supreme Court decision; but in Rule 4.3(c) it suggests that supplementary content associated with a particular court decision may be identified in roman before the name of the case. Consequently, I would consider the following format analogous to the one it approves for "citation to online copy":
Syllabus to Maroonbook v Blue Book, 666 US 999 (2014).
where "666" is the volume number in U.S. Reports (the preferred collection of Supreme Court decisions) and "999" is the page number where the syllabus appears.
On the other hand, if your work is not primarily legal, you're back at square one, trying to figure out the relevant Chicago Manual of Style style—and that book isn't especially helpful for handling legal citations. Still, at 16.106 of the 15th Edition, CMoS provides some basis for adopting the following bibliographical style:
U.S. Supreme Court. 2014. Maroonbook v Blue Book, syllabus, 666 U.S. 999.
The allied note form, closely modeled on CMoS 17.284, would be much the same as the bibliographical form except for the shifting of the year to a parenthetical at the end of the citation, and the omission of the institutional author:
- Maroonbook v Blue Book, syllabus, 666 U.S. 999 (2014).
where "1" is simply the number of the note in the relevant chapter or article.
Whatever style you adopt, you won't be able to point to a rule in Chicago that specifically endorses it, but I think that the styles I've suggested are in line with Chicago's preferences in related areas and should keep you out of trouble. For additional advice, I recommend consulting the most recent Harvard Blue Book (which I don't have) to see if it addresses your particular citation situation.
I would say yes, that is the correct way to go. The CMOS does not explicitly ask for licences, but it does not say they should not be there, either; in fact, according to CMOS 16, section 14.274 Audiovisual materials—elements to include,
Documentation of a recording usually includes some or all of the following pieces of information: the name of the composer, writer, performer, or other person primarily responsible for the content; the title, in italics or quotation marks, as applicable (see 8.192); the name of the recording company or publisher; any identifying number of the recording; indication of medium (compact disc, audiocassette, audiovisual file, etc.); and the copyright date or date of production or performance. Recordings consulted online should include a URL or DOI (see 14.5, 14.6). Supplementary information, such as the number of discs in an album and the duration of the recording, as applicable, may also be given. [my emphasis]
The CC licence information is clearly supplementary information in this context, albeit of a different type than the one they mention as an example.
In section 14.280 Online multimedia, they do not really say much that is very useful in the text, but the example citations given do give some hints, particularly the following example which quotes a YouTube video:
“HOROWITZ AT CARNEGIE HALL 2-Chopin Nocturne in Fm Op.55,” YouTube video, 5:53, from a performance televised by CBS on September 22, 1968, posted by “hubanj,” January 9, 2009, http://www.youtube.com/watch?v=cDVBtuWkMS8.
Adapting this for your photo credits, I would personally go with something like one of the following options:
“taxi,” Flickr photo, taken 11 December 2006, posted by Carolina Arevalo, 20 September 2010, https://www.flickr.com/photos/carolinaarevalo/5008340224 (accessed June 16, 2015). Licence at https://creativecommons.org/licenses/by/2.0.
“taxi,” digital image, taken 11 December 2006, posted to Flickr by Carolina Arevalo, 20 September 2010, https://www.flickr.com/photos/carolinaarevalo/5008340224 (accessed June 16, 2015). Licence at https://creativecommons.org/licenses/by/2.0.
(I would leave out your own description of the image in the Photo Credits section—that belongs as a caption to the image or in the body text, not as part of the credits.)
In cases where you do not have the name (or even a user name) of the photographer, but only their Flickr ID, you’ll just have to write that instead of the actual name:
“taxi,” digital image, taken 11 December 2006, posted to Flickr by user “13548987@NO9”, 20 September 2010, https://www.flickr.com/photos/carolinaarevalo/5008340224 (accessed June 16, 2015). Licence at https://creativecommons.org/licenses/by/2.0.
Best Answer
Here's a quotation from the [Harrisburgh] Pennsylvania Reporter, reprinted in the Political Register (December 24, 1832), on the subject of South Carolina's pursuing the possibility of nullifying its membership in the United States:
Then follows a comment by the editor of The Political Register:
As the excerpts show, there is some inconsistency in the periodicals' handling of the word union. The Pennsylvania Reporter lowercases the term when referring to "the union of the States," as though interpreting union in that setting as a descriptive term meaning something like "continued unity or conjunction," but capitalizes it when using "a Union" to allude to the United States and when referring to President Andrew Jackson's famous toast of April 13, 1830, to "the Federal Union" as a political entity. The Political Register, meanwhile capitalizes Union both when saying "the Union" (that is, the United Sates) and when saying "this Union" (again the United States).
From this evidence, I conclude that people before the Civil War were to some extent accustomed to seeing "the Union" used as an alternative designation for "the United States," and that it would be reasonable to capitalize it today just as it was capitalized then—and after the Civil War.
The case for northern and southern is far less clear, as the only instance in the excerpts is to "feeling in the south." Elsewhere in the same volume of the Political Register, however, are dozens of references to "the south," "the north," "southern," and "northern"—and in all of them, the words are lowercased (unless beginning a sentence or appearing in a headline). From this it follows that using the capitalized forms "the South," "the North," "Southern," and "Northern" may be anachronistic. I have seen many books that capitalize these terms anyway—presumably on the reasoning that today they would be capitalized, so why not retroactively?
I have mixed feelings about the capitalization of southern and northern. Historically "the south" and "the north" crystallized into "the South" and "the North"—and eventually the South tried to tear the Union apart. Ever afterward, "the South" and "the North" have remained the usual spellings for the two regions. Still, there is something hopeful and undetermined about referring to them "the south" and "the north" [of the United States] in connection with a time when civil war was not yet demonstrably inevitable. Ultimately, I think I would capitalize Southern and Northern in acknowledgment of the impending cataclysm, but it's a close (and subjective) call.
The Chicago Manual of Style, fifteenth edition (2003) offers a limited endorsement of uppercasing Southern and Northern in its list of examples of regional terms at 8.50:
Because Chicago comes out (at 8.2 of the fifteenth edition) four-square for what it calls "the 'down' style" ("the parsimonious use of capitals"), it may prefer southern and northern in any context not explicitly alluding to the American Civil War, but—as I noted earlier—I've seen many books that purport to follow Chicago and yet capitalize Southern and Northern in non–Civil War contexts.
Update (January 2, 2018): The guidelines in Chicago, sixteenth edition
After posting this answer, I acquired a copy of The Chicago Manual of Style, sixteenth edition, and can report that it retains the fifteenth edition's preferences with regard to southern/Southern and northern/Northern:
The omission of "a" before "Northerner" in the list of examples appears to be an editing oversight or consistency error and not an indication that Chicago advocates saying "Johnny Rebel is a Southerner and Billy Yank is Northerner."
Elsewhere, the sixteenth edition endorses "the Union":
So the sixteenth edition considers "the Union" to be properly uppercased in the context of discussions of the United States. The parochialism of this view—which seems to grant special status to certain descriptive synonyms for the United States—is unmistakable; but I suppose that if we were to examine The Istanbul Manual of Style, we would probably find that it endorsed "the Ottoman Empire" and "the Empire" while relegating the U.S.-related entries to "the United States," "the republic," and "the union."