  We consider the problem of reconstructing binary images from their horizontal
and vertical projections. It is known that the projections do not necessarily
determine the image uniquely. In a previous paper it was shown that the
symmetric difference between two solutions (binary images that satisfy the
projections) is at most 4A times the square root of 2N. Here N is the sum of
the projections in one direction (i.e. the size of the image) and A is a
parameter depending on the projections. In this paper we give a lower bound:
for each set of projections that has at least two solutions, we construct two
solutions that have a symmetric difference of at least 2A+2. We also show that
this is the best possible.
