I am not sure how you are distinguishing my theoretical protocol agnostic fuzzer from afl. Is afl a jpg/png specific fuzzer? One of the things that is great about afl is that it is not targeted towards a specific file format it can work with a small corpus or thorough dictionary of the target format. eg I can give afl-fuzz a snippet of two of markdown and it will go nuts or if I want to be exhaustive I can feed afl the afl "dictionary" from the commonmark testsuite.

How do you ever eliminate false positives when fuzzing? And what constitutes a false positive?