Some friends and I are looking into making a platformer. I'm doing the backgrounds. We're currently finishing up on a side-scrolling SHMUP and that was pretty understandable since all I had to do was make a background that could be put on a never ending loop like an old black and white movies from the olden days where they would have the characters run in place wall some guy on a bike was making the background loop over and over again.

Now where I'm puzzled for the moment is how to do a platformer game, especially if it's not one continuous straight line. Since I want for the level to not look exactly the same over and over again like a SHMUP, how do I go about making the background for the platformer? Do I just draw on giant picture and then the programmer will have a camera move through different parts of the background based on where the player moves? But I'm thinking that would take up a lot of space and memory. Or should I make the large level, but divide it into many smaller pictures and the programmer can have one screen load as the player is transitioning through the game. For example:

[1a]-[2a]-[3a]-[4a]-[5a]
***********\[3b]/***
^For that example I'm basically drawing 6 full screen backgrounds.

I'm just wondering how they do backgrounds for games like Castlevania, Super Metroid, Metal Slug, and so on. They seem so varied with the design, even when moving with the same area/level.

If it's a PC or console game the amount of memory taken up by a large background image is negligible. Making one large image is the standard way to do it as far as I know.

Well the game we're making, we plan to put it on Xbox Live Indie Games. The current plan is to make sure the game doesn't go over 50 mb in size.

Why don't you make a bunch of Backgrounds, all of which can be arranged from end to end in any way (the end of one background, can sync with the start of all the other backgrounds. do this for every background), so that it looks like its continuing from the previous image.

And then you can have the programmer loop these images randomly.

As the every image can fade into every other image, and as they will be randomly arranged, the player wont get a repetitive feeling.

Hope you get what I'm saying. :)