Look at the images and captions in books to identify primary resources. They sometimes provide the source of the original materials. Also check for sources in the "Photo Credits" or "Acknowledgements" sections. Once you have that information, you can contact the owner of the original material or track down its location.
What are primary resources?
Primary resources are original works, often firsthand accounts that have not been filtered through interpretation. These include eyewitness accounts, original works of art, original photos, novels, historical documents, interviews, letters, diaries, raw data, and autobiographies, among others.
Secondary resources, on the other hand, are a degree removed from the original material. They are interpretations, analyses, or summaries. These include book reviews, essays, criticisms, and commentaries, among others.
Check out the video below for more examples.