For a taste of what it contains, have a look at http://linux-sunxi.org/LiveSuit_images.
A LiveSuit image is more than just a collection of partition images. It contains information on how to configure the hardware of the device (e.g. the pin functions of the processor), how to set up the partitions (sizes, type etc) and also contains various tools (checksums, hardware testers) used by LiveSuit itself during the flashing process.
A LiveSuit image is the only solution possible if the internal storage on the tablet has been completely buggered (unable to boot).
Needless to say, it's nearly (well, probably completely) impossible to create a working LiveSuit image from scratch. The best way is to get a working stock LiveSuit image, unpack it, make the required modifications (such as changing partitions) and then repack it. This is a bit of a finicky process and is described elsewhere in these pages.
Although Uberizer has an inbuilt option for unpacking and repacking LiveSuit images, I couldn't get this to work and had to do it manually.