Public domain works are not copyrighted and do not require a fee or licence to use. This allows the user unrestricted access with free of charge.
Following are some of the public domain works which are not copyrightable.
- Names, titles, slogans and symbols
- Processes and systems
- Ideas and facts
- Government work and works assigned as public domain by creators
Hopefully following sites would support you to find some public domain images and free eBooks.
My eLearning Techniques 