Thanks for this! I didn't know about the thumbnail or preview, and I hadn't figured out what the "Separations" value meant -- Do you think they mean "Color Planes" by "Separations" ?

But there are 2 more values after YEND that you don't mention. I have decoded the second as CropRotation, but still don't know the meaning of the first (I have only seen a zero here).

And do you have a reference for this specification? I would like to add this to the documentation if possible.

I have added the ThumbnailImage, PreviewImage and ColorPlanes tags, and uploaded a new 6.51 pre-release for you.

- Phil