Close
FWIW it was crashing on 8bit images ~17000x21000 in size.

The issue seems to be that the Greyc-helper.bin is not 64bit, so it crashes when reading the image at the following line in Protocol::ReadImageData(CImg &img) :

ReadCommandData(img.m_pData, img.m_iStrideBytes * img.m_iHeight);