Creating a cover from public domain images

Today, GalleyCat on mediabistro.com heads up with list of places to find PD images.

Coincidentally, the jacket background of the third in the Promise of Gold trilogy, Dearest Enemy, is one such image.

It is a view of Sacramento City from the Embarcadero, about the year 1850, showing the foot of J Street, where the Gosling Company's theater was built. Coincidentally, there is a brig moored up to the waterfront, exactly where the brig Gosling is moored in the story.

The original is panoramic, so this is just a fragment of it.

According to Wikimedia commons, where I first found it, it was used as an illustration called "Sacramento-City in California" in a book called The United States Illustrated, by Charles A. Dana (New York, 1855).

That is by no means the only book where it has appeared, and there are plenty of copies of the original lithograph, too.  It is featured on many public domain sites, including the Library of Congress, which gives a detailed history of the engraving.  

Title: Sacramento city, Ca. from the foot of J. Street, showing I., J., & K. Sts. with the Sierra Nevada in the distance / / C. Parsons ; drawn Dec. 20th 1849 by G.V. Cooper ; lith. of Wm. Endicott & Co., N. York.

Creator(s): Parsons, Charles, 1821-1910, artist

Related Names:
Cooper, George Victor, 1810-1878 , artist

Date Created/Published: New York : Published by Stringer & Townsend, c1850.

Medium: 1 print : lithograph, tinted ; 43 x 60 cm. (sheet)

Reproduction Number: LC-DIG-pga-04015 (digital file from original print) LC-USZC4-2853 (color film copy transparency) LC-USZ62-93402 (b&w film copy neg.)

Call Number: PGA - Parsons--Sacramento City, Ca. ... (C size) [P&P]

Repository: Library of Congress Prints and Photographs Division Washington, D.C. 20540 USA

So, there is a rich repository of images that can be used for book jackets, many of them in high definition, and many ways they can be found.

The list, given by GalleyCat:

1. The Library of Congress’ image collection to find public domain images
2. American Memory Project to find public domain images
3. Archive.org for public domain books
4. Public Domain Images Google Search
5. Illustrated books on Project Gutenberg
6. Creative Commons search on Flickr