Is there a way to replace placed pics in keynote, with other newer version pics (eg. like Illustrator replaces linked files)?
Or do i have to do the whole thing (insert choose) all over again?
AFIK there is no mechanism in Keynote for linked objects of any kind. However, given the problems I have had in the past with linked objects in PowerPoint I have never missed them because I never use them.
Linking objects in my perspective, is awesome because when modified, they simply update and you dont need to place the same pic over and over again once you finalize it!