I mostly upload my own photos; somewhere under ten percent of my uploads are either public domain material or from sources such as the Seattle Municipal Archives that free-license interesting photos. Here are some examples of my uploads of other people's work.
I uploaded and annotated the contents of a rather remarkable 1900 booklet called Seattle and the Orient. Amazing stuff (although the "and the Orient" in the title is mostly a business pitch.)
The old King County Courthouse on Profanity Hill
The Waltham Block: this now houses the Davidson Gallery and the Glasshouse
The Terry-Denny Building (at that time The Northern Hotel), still there (on the west side of First just below Yesler)
Looking west on James Street toward Pioneer Square; the two buildings in the foreground still survive, as does part of the second building from the right, and a few that can be seen in the distance (though, sadly, not the Seattle Hotel, second on left, or the Olympic Block, dead ahead).
Railroad Avenue along the downtown waterfront (now Alaskan Way)
Centennial Mill (flour mill at the foot of Yesler Way)
Tinfoiling Rainier Beer bottles
Inside the hull of a ship under construction in Moran Bros. shipyard
The Seattle Room at the Seattle Public Library is an another great resource. Among the many things I've found there are:
A 1905 Rainier Beer ad from a Polk's Directory...
... but I think this one from The Argus Alaska-Yukon-Pacific Exposition special issue (1909) is even more fun.
An 1899 ad for Heckman & Hanson Shipbuilding Co.
A 1904 map showing the route of the Duwamish River by Georgetown and South Park before it was straightened
An 1893 map showing the old street names in what are now Wallingford and the University District
Elements of this 1912 photo from the Seattle Post-Intelligencer...
... were photo-collaged (part of it reversed) and hand-colored on the cover of this 1915 book.
Seattle's first (horsedrawn) street car at Occidental Avenue and Yesler Way, about 1884. The view is across Pioneer Square. The building in the background stood on the present site of the Mutual Life Building at First Avenue and Yesler Way. The building on the right was the Occidental Hotel, destroyed in the Great Fire (1889), replaced by the and the Seattle Hotel (which was demolished in 1961 and replaced by the "Sinking Ship" car park.
The SS Tacoma under construction, one of the fastest steamers in the Puget Sound mosquito fleet
And from some other sources...
Pioneer Square, Seattle, circa 1906. Rob Ketcherside actually found this one & uploaded it to Flickr; I brought it over to Commons.
Seattle's old waterfront fire station, replaced by a new building in 1917 and again in 1963. From the Municipal Archives.
Seattle City Light Director of Home Economics Mary Norris, 1954. From the Municipal Archives.
Space Needle under construction, 1961. From the Municipal Archives.
Looking through the 1909 Tyee (University of Washington yearbook), I came across some wonderful cartoons and drawings by a man named Olaf E. Caskin, who I gather remained in Seattle and worked mainly as a commercial lithographer. I've uploaded a number of them in Category:Olaf E. Caskin illustrations in 1909 Tyee. Here are a few of the best. And remember, this is 1909: years before Will Eisner.
Not always my own uploads, but I've been heavily annotating some old Seattle views, mostly street scenes; you'll have to click through to see the annotations, though:
1st Ave looking north from Cherry St, circa 1890, west side of street.
1st Ave looking north from Cherry St, 1906, west side of street.
1st Ave looking north from Cherry St, 1909, both sides of street.
The great Asahel Curtis, who worked mostly in and around Seattle in the early 20th century, often took multiple photos from the same spot to give the sense of a place. I've been stitching these together into panoramas:
New Western Hotel, 817 3rd Ave at Columbia Street
Moran Brothers Shipyard, Seattle, showing machine shop and battleship shed.
Seattle from Centennial Mill, 1902
Fremont district and north end of Lake Union from Queen Anne Hill, 1902
Intersection of Columbia St. and Summit Ave., First Hill, c. 1903. This would now be somewhere in the middle of Swedish Medical Center First Hill.
Green Lake neighborhood and lake, circa 1903
Intersection of Boylston Ave E and E Mercer St, Capitol Hill, c. 1903
Stimson Mill, Ballard (still an independent town at the time), 1904.
Ballard from Queen Anne Hill, c. 1904
Galbraith, Bacon & Co Wall Street Dock and warehouse, with sailing ships in background, 1906
Green Lake and Greenlake neighborhood, Seattle, 1906
Brooklyn District (Latona & University District), c. 1906
"The last of Denny Hill", Aug 20, 1907
Columbia City, 1908
Moran Bros Co shipyard, Railroad Ave. S near S Charles St., 1908
Pleasant Valley, Magnolia district, Seattle, 1909
Bolcom Mills, Ballard, 1910
Tacoma manufacturing district and tide flats, 1912
Seattle from Post Street powerhouse, February 23, 1913
Seattle from Beacon Hill, 1914
Empire Addition, vicinity of S Orcas St, 1916
Seattle waterfront and Railroad Ave (Alaskan Way) at foot of Wall St., 1916
Ballard Locks (Hiram M. Chittenden Locks), 1917
Seattle harbor and shipyards, including Harbor Island, from the south, 1919
One by Frank H. Nowell, official photographer of the Alaska-Yukon-Pacific Exposition (Seattle, 1909):
Court of Honor, Alaska-Yukon-Pacific Exposition (Seattle, 1909) faturing Geyser Basin & Manufactures Building. Left to right: A tiny bit of the U.S. Government Building is visible, with the cupola of the University of Washington Building now known as Denny Hall peeking out over it; then Hawaii Building, Oriental Building, Manufactures Building, King County Building, Machinery Hall. Statue of an ox visible in front of south (righthand) portico of Manufactures Building.
And one by Wilhelm Hester:
Wilhelm Hester panorama of Great Northern Railway Ocean Dock, Smith's Cove, Seattle, Washington