Before-and-after QR scan: compare payloads, not appearance

Two QR images can look quite different while encoding the same payload, and near-identical images can encode different URLs. Scan both versions and compare decoded text character for character. If the intended change was only size or color, verify the payload stayed the same and that both remain readable under realistic conditions. If the destination changed, confirm the new link's domain and behavior. Appearance alone cannot establish QR correctness.