Hi eNGiNe,
In Word 2010, it appears that linked graphics that are stored in the same folder as the docx file in which they are stored do maintain their links when the lot are moved to a new folder. This doesn't apply to doc files, though, or to links stored in different folders than the docx files.
If you have a document open when its linked graphic is updated, the update should be reflected in the document immediately the changed graphic is saved.
FWIW, if you're working with doc format files, you can access a linked graphic's INCLUDEPICTURE field, via Alt-F9, for example. This can't be done with docx files (though you could save as doc, access/edit, then save back to docx).
If you're inclined to move files and graphics, you may be interested in how to implement relative paths in Word, per the solution I've posted (#8 in the thread) at:
http://windowssecrets.com/forums/showthread.php/102080