BUG: Fix overflows computing size of read tiff image

When multiplying the height and width of an tiff image (32-bits),
at least one element should be converted to size_t to help prevent
numeric overflow.

This change enables reading of larger RGB and large 2D image, that
were previously truncated when reading. This does not address
potential buffer overflow or resource limits which could occur.

Change-Id: I192370606677c8dc1a903c67c2a0701026256d5a
Merge topic 'FixBigTiffOverflowRead'

6791b4a3 BUG: Fix overflows computing size of read tiff image