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PNG PARSER DIFFERENTIAL

This PNG image renders differently in Apple vs non-Apple decoders:

If you're using Apple-flavoured software, you should see "HELLO APPLE", and on
all other software, you should see "HELLO WORLD".

I found this while writing my own multi-threaded PNG decoder. While pondering my
design, I realised that I had an exploitable implementation bug. After learning
that Apple has their own implementation of parallel-decodable PNGs, I realised
that they'd made exactly the same mistake!


UPDATE:

I created a tool to merge arbitrary full-colour images. Here is an example: