1993.08.23 10:58 "help on TIFFReadRGBAImage", by Oliver Trepte

For what it's worth, the PPM standard specifies that the first pixel in the file is in the lower left corner. This is always the case, and it can't be set to anything else from within the PPM file.

Shouldn't it be top-left corner? The ppm(5) manpage reads:

Oops, you're right. That's what I meant. A small typing error...

Oliver