The AndEngine framework for Android has a way to load textures into an atlas. The atlas way of loading textures was new to me and so I looked into it. From what I've read around the forums, an atlas is a large rectangular region of image data where the width and height have to be powers of 2 (although they don't have to be equal, i.e. you can have a 512x1024 if you want). Textures are loaded into this region and this is used to keep them all in memory during the lifetime of the app. It allocates all of that space even if you don't use some of it.
With that in mind, what process can I use to optimally place an arbitrary number of graphics into the same atlas? I don't plan to do this at runtime within the app, but once all the graphics for my game have been created, I was hoping I could run the images and their sizes through some algorithm to determine how big to make the atlas and where each image should be loaded in it. Once I know those things, I can hard code their location for my game.
This is not an AndEngine or even Android specific question. I'm sure there are other graphics oriented frameworks that load textures this way.
I was about to post the question on Math.StackExchange.com but instead I found that it was already asked and already answered. There's even a link to a CodeProject article that does this for CSS Sprites.
EDIT: What I ended up doing in the long run was using a program called TexturePacker. Not only did it pack the images, it produced files to be used in AndEngine (as well as other supported platforms) and made the whole process easier for me.