Apparently the image links are root paths.

So, if you recreate the path that the original file was created on a different computer, then the image links will work.

For example:
When creating a file with linked images (in the same directory), the path might be

/Users/mars/Desktop/Local Work/Project/chart.graffle

So, image links will continue to work, if on any computer where the file is used, it is still located at that path.

Inconvenient yes, but an *ss-saver indeed.

*Mars