In this paper, we propose a format compliant feedback encryption scheme for JPEG2000 by using a chaotic pseudo-random bit generator. This chaotic pseudo-random bit generator is purturbed to enhance cryptographic properties such as cycle length and statistical properties so that it can be used to construct our stream ciphers with higher security. The encrypting time by using our proposed scheme is calculated and compared with other scheme. In order to demonstrate the key sensitivity, we test the performance of our proposed scheme with one of the parameters being slightly changed.