Created attachment 8445 [details]
screenshot of eog

Could you verify if this also occurs with older versions of 
io-tiff.c ? The reason I'm 
asking is that I changed the latest
version (1.32) to directly copy stuff into the 
pixbuf instead of
dumping it into a separate buffer and copying individual 
samples
with TIFFGet[RGBA]. But since then I've found some hints in the
libtiff 
mailing list and bugzilla which seem to indicate that the
actual sample order used 
by the TIFFRGBAImage API depends on the
host endianness. 

actually i always get endianness wrong, and the PPC is BE isn't it?

i'll look at this tonight, thanks.

yep, updating to 1.31 and reinstalling the tiff loader makes it work.

Ok, I'll look into fixing this. Simply reverting to 1.31 is not 
good, since there is a 
number of robustness fixes in 1.32 in addition
to the problematic change.

Would you mind testing if the following patch (against io-tiff.c 1.32)
works on PPC ?

Created attachment 8520 [details] [review]
the patch

i tested this patch on x86 linux and ppc mac os with both LE and BE
tiffs, and it works.