ff_grey_cross.gipl was provided  courtesy of Dr. Eddie Edwards at Imaging Sciences, CL, Guy's Hospital.

ff_grey_cross.gipl is a simple 9 x 9 x 9 gipl image with pixel dimensions of
1mm and origin of (0,0,0). The image is a 3D cross, with the middle voxels set
to 1000 and the background set to zero. I used to use this to check that my
display software gets the 'half voxel' display position right. The standard
origin for a gipl is the centre of the image, i.e. the centre of the cross.

One other thing to bear in mind is that the byte order for gipl data is 
always
big endian.

