Some words of advice for public domain image searchers and uploaders:

  • Don't upload old scanned photographs as .png. If you copied it from the internet, the quality of .png photos often sucks when scaled, and will look even worse in Wikipedia or elsewhere. See Commons:File types for more info.
  • Use Internet Archive, not Google Books: the non-profit Internet Archive often hosts the same books and media as Google Books, and often in much higher quality (sometimes in full color!), and sometimes multiple versions of a book, magazine, or document. Search for the highest quality version of an image. Google is not your friend.
  • Search HathiTrust, not Google Books: similar to the above. The non-profit HathiTrust digital library hosts millions of documents, including public domain material scanned by Google Books. The for-profit Google Books sometimes systematically censors images and photographs from its scanned (public domain) publications. Lord knows why (but it probably ultimately has something to do with profit). There is material at HathiTrust that is not found by a simple Google Search. Google is not your friend.
  • Don't rely on Google alone. I'm not fundamentally opposed to Google (I'm currently typing this in Chrome!), but there is a vast trove of free information that can't be accessed by typing into a Google search bar. The so-called deep web and other non-indexed sites includes a ton of newspaper and magazine archives. If you have a newspaper subscription and/or a public library card, you can often find tons more online public domain material that doesn't come up when you Google (or Bing!) "John Q Famous Person".
  • Don't rely on the internet alone. If you have public domain books, magazines, newspapers, photographs, or works of art at home, by all means scan and upload them! If you find high quality material at libraries, scan and upload those too! There's a very good chance your upload will be better than anything else on the internet, since digital libraries and archives often have to consider file size, and opt for low quality, low-resolution black and white scans.
  • A little editing goes a long way. A lot of scanned public domain images have various problems, from unwanted Moiré effects to a photographer's thumb in the frame. Consider cropping out or digitally removing unwanted elements (the heal tool in Gimp or Photoshop is great for removing blemishes, ink spots, bleed through, and other artifacts). Sometimes simply converting an image from color to grayscale (desaturation) alone can significantly reduce Moiré distortion and improve image quality.