Public Domain images are 'publicly available' and not covered by intellectual property or copyrights. There are many stock photography websites out there.
Four Vintage Hot Air Balloon Images. Free public domain images of Victorian hot Air Balloons.
6 Free Websites For Public Domain Images & Free Stock Photos image
A free printable for projects: vintage lavender salt advertisement
Free Public Domain Vintage Image - Stunning Roses - The Graphics Fairy
The Graphics Fairy: Public Domain Rooster Image