JPEG / JFIF

TIFF is certainly complex, but that's made up for by its unmatched power and sophistication. I've recently been working on TIFF reading/writing of microscopy imaging data, and testing all the different combinations of PhotometricInterpretation with and without LUTs, pixel type and depth (including complex floating point types), orientation, large numbers of channels, all sorts of combinations of tile and strip sizes, bigtiff, etc. It's quite surprising how many programs and graphics libraries get it wrong. The worst I found was the Microsoft TIFF support on Windows, e.g. for thumbnailing and viewing, which was incorrect for most cases, and apparently it's been much improved! Support on FreeBSD and Linux with free software viewers was better, but still not perfect for many cases.

I think this is primarily due to most authors staying well inside the 8-bit grey/RGB "comfort zone". Sometimes this extends to 12/16-bit or maybe float, and not testing with more sophisticated data.

Most of that is simply the author screwing up. For example, when dealing with strips and tiles, it's amazing how many people mess up the image data by failing to deal with the strip/tile overlapping the image bounds when it's not a multiple of the image size, sometimes for particular pixel types e.g. 1 or 2 bit data. Just a simple miscalulation or failure to check particular tiff tags.

I'm not sure what the solution is here. A collection of images which exercise usage of all the baseline tags with all the special cases (and their interactions) would be a good start. I currently generate a test set of around 4000 64×64 TIFF images for the set of tags I care about, but it's still far from comprehensive. I know it works for the most part, but even then it's going to fail for tags I don't currently code for.