What are the limits of Image spells?
An example in the 'All about Illusions' articles on wizards.com (1, 2, 3, 4) is an illusionary guard: Can I make the guard (keeping concentration) dissolve into smoke (and grant concealment with the smoke)?
Or more general: Can I morph/transform/change the illusion while the spell is on-going?
And: A monster who tells his friend that something is an illusion grants that friend a +4 bonus to the will save. However, the friend still needs 'an action' of his own to interact. What action? (Standard, Move, ...)
I would prefer answers including rule text references, if possible. References to related material or other discussions of the possibilities and limits of the image spells are very welcome.