Standard Way of Animating Images?

Hey guys,

So I am making a game. There are usually quite a few images on the screen, and usually a whole lot more that are pre-loaded, which usually adds up to about 500 or so images in the ram that have been loaded into an array. (BufferedImages, not Images if that makes a difference. Don't see why it would, but doesn't hurt to mention.)

I was reading somewhere that some people turn their images into an array of bytes, and then draw them from there. I have a couple of questions.

Does it make a difference, when storing data in RAM? I was monitoring the system resources in the Task Manager, and saw that the game was taking up 43,000kb of space, and that was with only 5 or so images loaded.
Will it make a difference in loading them into the game? Loading a pre-loaded image is incredibly fast, and with double buffering there is no "choppiness" in the painting.
Is there another, more standard way of animating, that doesn't involve loading a sequence of images?

Anyways thanks for any help, and sorry if this is a repeat question. I search the forums and couldn't find anything that gave me a specific answer.