InDesign can create a “package” containing all of the resources used to create a document. The images in an InDesign document are low-resolution placeholders linked to full-sized images stored elsewhere on the system. When I create an InDesign package, InDesign creates a package that contains all of the document’s resources, including a copy of the InDesign .indd file and copies of the linked images. InDesign changes the image links in the .indd file to point to the images in the package directory. The package is now a clone of the original project. It stands on it own and can be sent to another person for editing. Who knows, I might someday have to send my Jaybird book to an editor, graphic designer, collaborator, etc. so that they can work on my project with a complete set of files.
In the example below I have opened the InDesign document contained in a package. When I edit the images in the package, the images will automatically be updated in the package’s InDesign file.
This example shows a page containing a low-res copy of a PSD file.
I edited the image in the package Photoshop and turned off the color layers.
When I return to InDesign, I can see that the image has been automatically updated. This is very cool!