Hi Mark,
FWIW: I ran your test program on my Retina's integrated HD 4000 (VRAM 512 Mb) -- with the provided texture 6000x4500 it runs fine. I then created a 12000x4500 image and the program crashes with the integrated card, while it still works with the NVIDIA GeForce GT 650M (VRAM 1024 MB)
If my calculation is correct (6000x4500x8 = 216 MB and 12000x4500x8 = 532 MB, assuming 8 bytes per pixel) this behavior is in line with HD 4000 memory rating at 512 MB. If it's 4 bytes per pixel, the 12000x4500 crash would be a surprise, but still could be perhaps explained by the memory overhead a texture requires on the GPU.
--8