If you are providing a Publisher file, then use the Pack and Go scenario (on
the file menu). This will save out the indvidual images and create links for
them.
Having files linked instead of embedded usually creates fewer problems at
the output end ... while this may not be true with Publisher, it certainly
is with other apps. Embedded images in PageMaker, for example, will bring up
warnings that need to be investigated before one outputs the file. Quark has
no provision for embedding. Etc. (it also make it easier to fix the linked
images...converting to greyscale if needed, adjusting tonality for better
reproduction, etc)
I do not like to see files come in with everything embedded because I have
no quick way to know if this full page bleed images was a 2x3 72dpi
"internet" image before it was copied and pasted as the cover for a catalog.
Now...if you are not providing native (Publisher) files, but PDF or PS
instead, then there is no need for the images to accompany the files
(assuming the files, pdf especially, were built correctly).