compositing

iMovie offers much more than a hard cut.

Pic-in-Pic

.. 'as in the news', the lil' window to the world aside the host

read iMovies Help/Manual

a few remarks:
• importing a .png allows transparency! 
• only one pic possible
• it can not be moved
• you can do funny things, when pic and studio have the same color!

Green-Screen

• in my experience, the background should NOT plain green, in iMovie it works best being greenish. when you use  static picture, e.g. in some paint-app, use the cloud-filter to generate a patchy bg. visit the green-screen-subsite CLICK .

• some users tells us: record a few second 'background only' to teach iMovie the green



Transparent .PNG

read my advice on my 'Tricks' Main Page .. my main site CLICK )
• it allows adding arrows, speech-bubbles, high-lights
• it allows your own titles and lower-thirds
• it has some limitations