Bingo, error detection is functionally distinct from error recovery. In this context, error detection helps prevent some misdeliveries, but can't help ensure additional correct deliveries in the face of error.
By analogy, ECC memory can typically detect two bit errors but can only correct single bit errors. That's because the functionality used to detect two bit errors in ECC memory is insufficient to recover both bits.
The concept of an avatar doesn't translate across cultures. And the visual hash isn't an "avatar" as typically used on the internet. Furthermore, the images may be incomprehensible in some cultures.
Keeping a minimal edit distance between code words in the corpus would enable error detection and correction without the burden of sending another piece of info.
By analogy, ECC memory can typically detect two bit errors but can only correct single bit errors. That's because the functionality used to detect two bit errors in ECC memory is insufficient to recover both bits.