I am coding a simple 2D engine to be used with HTML5. I already have classes such as Picture, Scene, Camera and Renderer, but now I need to work on Animations.

Picture is basocally a wrapper for a normal image object, with it's own draw method, but this is unrelated, I'm interested in how animation in 2D games is usually done.

What I planned to do, is to have the Animation class as well act like a wrapper for a few image objects, and then have methods such as getCurrentImage, next and animate (which would use intervals to quickly change the current image). I meant to feed the animation a couple of PNG's at inicialisation.

Is quickly swapping PNG images acceptable for 2D animation? Are there some standard ways of doing this, or are there flaws in my ways?