[just_for_you]

One form of true insanity is probably JPEG-encoded TIFF files. Apparently it's so bad that for the next version of the TIFF specification they are taking that insane approach out completely.

I can't do justice to the article on TIFF's problems with JPEG (http://www.simplesystems.org/libtiff/TIFFTechNote2.html), but my understanding is that:

1) Some JPEG-specific data is moved outside of the actual JPEG bitstream tag, and into separate TIFF tags, making editing JPEG-in-TIFF files non-trivial. 2) Size is not encoded in some of these fields, so the TIFF editor you're writing will have to partially implement a JPEG decoder just to know the size of some of those TIFF tags, and 3) Some tags/fields are pointers into other parts of the TIFF file, meaning if you edit the file, you'll have to update the file in many places.

(As a quick aside on insane formats, may I also mention the EPWING dictionary format?)