common/image.c: Use correct suffixes for binary sizes

IEC 80000-13:2008 Quantities and units
Part 13: Information science and technology

defines the prefixes to use for binary multiples.

So instead of writing
Data Size:    6726132 Bytes = 6568.49 kB = 6.41 MB
in dumpimage we should write
Data Size:    6726132 Bytes = 6568.49 KiB = 6.41 MiB.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>