The advancement of quantum communication technology is poised to revolutionize the current landscape of information transmission. Shor's algorithm is expected to break RSA encryption, which may challenge traditional encryption methods. Therefore, mixing quantum and classical theories will be an important issue we must face. This paper proposes a real-time image encryption method based on reversible quantum gate computation. The FPGA is used to implement quantum gate manipulation and instant plaintext image encryption, and the encrypted image is stored in an SD card. A secret quantum gate key is transmitted via Superdense coding using a pair of entangled qubits. The decryption of the encrypted image is achieved through reversible quantum gate computation, offering a way for real-time image encryption methods.