Everything is based on a 32x32 block, as follows:
If there are more, the second block is always to the right of the first.
For example, if the hexadecimal numbers represent 32x32 blocks, they are laid out in this order.
The smallest image is technically a 32x32 block, with "blanks" appended.
So, as a more concrete example, this image (in 8x8 blocks)
Really looks like this to the game ('.' represents a blank 8x8 tile):