Is it attainable/possible for nodes to redact data (for instance inappropriate photos) of their blockchain and stay a part of the community?
Sidenote:
Though OP_RETURN was supposed for embedding small quantities of knowledge, I consider virtually all circumstances of embedding of photos within the final 12 months use OP_FALSE OP_IF <a number of knowledge pushes> OP_ENDIF inside an in any other case regular script in a witness element. This avoids limitations imposed on OP_RETURN and features the Segwit low cost on transaction charges.
Censoring transactions:
Pruning nodes discard blocks which were validated and whose content material is not needed for sustaining UTXO state. It have to be possible to be selective and have particular standards to discard knowledge that’s undesirable. For Bitcoin Core I think about it would necessitate rewriting giant blockfiles or some technique reminiscent of overwriting parts with say zeroes and updating indexes accordingly.
Not relaying unconfirmed transactions of this kind has been prompt. As Michael Folkson commented, giant photos (e.g. a number of MB) already cannot be relayed by Bitcoin core nodes due to its default coverage guidelines. publishers of huge photos need to make direct preparations with miners.
Nevertheless, the above nonetheless requires that nodes obtain and validate new blocks, no matter content material, as a way to keep UTXO state. So the aim can’t be fully achieved.
I consider additionally it is computationally infeasible for regular nodes to tell apart inappropriate photos from acceptable photos. Moreover, Individuals who embed such photos can take countermeasures to stop their detection.