I need to load in very large images, and it seems the only way to do this will be as a byte[] array.

Problem is: the data will be in its compressed format.

Any ideas? Obviously a PImage container can't hold it!

sorta depends on what you're trying to do. if you just want to grab a huge jpeg and render it to the screen and are using the default JAVA2D library, then you might try using Java's Applet.getImage() and then grabbing the Graphics2D object from the renderer and drawing it yourself using a java2d call instead of using p5 (getting the g2d is covered in the faq).

if you're using a different renderer, it gets a little more complicated. it also depends on whether you're trying to quickly scroll around to different sections, and whether you have control over the source files. for instance, if you have control of how the files are generated, then you could do something like storing a series of files that contain the image broken up (or at multiple zoom levels).. think google maps as far as that sort of implementation works.

generally if you're trying to move through a lot of data, there's a tradeoff that happens between the amount of time it takes to read uncompressed data from the file versus the amount of time to grab a small chunk and decompress it. in general, compression means you can't randomly jump through the file.. you could use a RandomAccessFile to allow yourself to read the raw bytes from different locations in the file as needed, but the image would need to be uncompressed (something simple like tga, for instance).

soo.. there are lots of options, just depends on what you're trying to do, and what your constraints are.