jm §nÔ7±ÎW(-ë%1A~ÎAh¶ð¬âLThe URL is stored on-chain - we were considering adding image hashes as well, but decided to keep it simpler for now. Yes, the ID is a cache-buster :)
https://whatsonchain.com/tx/b0aff7e40c1640cfa1140a7c765b3c4f5dde54e8379bb62baecaf89166f98b58