Old books and postcards.
Punch from 1850-1920 is often used for B&W sources.
Shopped, colourized and TOAPed for cheap laughs.
Overall, I like mashing old cards the best...

(
Tahkcalb ω∞ for sigs, Sun 10 Feb 2008, 2:16,
archived)
Great colorisation, man.
They always make me laugh even if it's "just" TOAP.
The title or text is usually the thing that makes the gag work, I think.
The opposite of Mac from the Daily Mail, in fact.
(
Bingowings Up your fucking borstal!, Sun 10 Feb 2008, 2:23,
archived)