Your First Game from Scratch: The Pong Game - Learn GameSalad for iOS: Game Development for iPhone, iPad, and HTML5 - page 37

There's a little secret to make it work nicely. All you artwork must have
a pixel size that you can divide by 4. Why 4? Because, to nicely
display your artwork, it must be an even number (like 20x20).
GameSalad will adjust automatically to lower resolution (i.e. divide by
2), so it needs to be an even number! Thus the 4!
Word of caution: there is a size limit of 1024x1024 for images.
If you are planning a low-resolution game (480 x320), there's no need
to check resolution independence. Another good reason to deselect
this option and plan for a low-resolution game is that older devices
(like the first generation of the iPod touch) will have difficulties to
handling those graphics. As ever, the best advice: test, test, and test
again.
The pages you have read thus far mention actors, scenes, and projects. So you
may naturally ask yourself, ''Am I reading the right topic? I thought I was reading
about game creation and everything looks like movie production. I don't have
the money to hire Bruce Willis for my production!''
Yes, you are reading a topic about game design. But isn't it easier to think about
game creation like a movie production where you have a plot (game mechanics),
some actors (characters or objects), and a direction (behaviors and attributes)?
GameSalad allows you to design your game like a movie. You will use scenes
(splash screen, menu, level, gameplays) and actors to interact in these scenes.
Adding Actors
Ready to play the movie director…er…the game director role? Let's fabricate
some actors!
What is an actor?
An actor is an object with specific behaviors and attributes that you will place in
the scene. Typically, in the Pong game, the ball is an actor. As for specific
behaviors, you will tell the ball how to react when colliding with some rackets
and with walls. The ball will also have some attributes that will define the ball
itself; for example, it will be moveable.