I do not know of any built-in option that does support this, but once I found the file names of the image files by opening a copy of the .iba file in a text editor that lets you view binary files, for example in Aquamacs Emacs. The image filenames will clearly stick out, even if all other content is a mess:
For example, searching for jps:
Or even simpler, use the Terminal to dump the iba-file with "strings" and search with "grep" for ".png":
Enter this line: (replace the red line by the path to a copy of your iba file)
strings ~/Documents/myDocuments/iBooks/Rezepte.iba | grep ".png"
strings ~/Documents/myDocuments/iBooks/Rezepte\ copy.iba | grep ".jpg"
Beim Abschiedsdinner, Kobe.jpg
Am Lake Chuzenchiko, Nikko.jpg
Weinprobe mit Chianti Classico.jpg ....
To create the pathname to your file you can simply drag it from the Finder into the Terminal window after typing "strings ".