Kevin,
If I understand you correctly, you have created the doc1 folder, inside is the doc1.book, *.fm files, and an images folder. One of the *.fm files references the A.jpg image in the images folder.
Create the doc2 folder, then copy all the files and folders inside doc1 to inside doc2. Do this in Windows Explorer, NOT FrameMaker.
Rename the doc1.book inside the doc2 folder to doc2.book. Everything should be as you want it to be.
NOTE that if you open doc1/*.fm in FrameMaker and then save it as doc2/*.fm, then FrameMaker recalculates the path to A.jpg to point to the file doc1/images/A.jpg, because FrameMaker assumes you want to retain your links to the original image files. The difference from the procedure above is that you are doing the copying within FrameMaker, not within the Windows file system.
Van