Since magic resistance keeps out magical things, doesn it keep out illusions?
That’s a pretty astute question. The Fifth Edition rules did anticipate this detail. Under the description of the Form of Imaginem on p. 79, the text explains that Imaginem spells produce non-magical species that can’t be magically resisted. So, any Imaginem spell looks the same to a person with magic resistance as it does to one without it. Incidentally, this rule also prevents the detection of visual illusions at Touch range by simply seeing (touching with your eyes) the species. You would need to touch the actual object that is the target of the Imaginem effect, or use a Voice- or Sight-range spell.
