If you spend enough time sifting through blogs, you will discover a very generous creative community. There are projects and ideas and plenty of visual inspiration, but there are also websites and blogs solely devoted to offering free, public-domain imagery to be used for all your creative needs. I would be remiss if I didn't share these valuable resources. Here are some of my favorites:
Just Something I Made Vintage labels, photos, graphics - and inspirational projects to go along with them.
The Vintage Moth Old photos, maps, postcards, ledger pages, illustrations, and the like
Vintage Printable The mushroom print shown above is from Vintage Printable. They have a wide range of images available, from a variety of sources.
Botanicus A library of botanical prints to use
Vintage Holiday Crafts Lots of colorful, vintage holiday illustrations, cards, and postcards
The Graphics Fairy A wide variety of resources, from old ledger pages to illustrations, vintage postcards, and wallpaper prints