JPEG2000, the latest international image compression standard, owns many unique characteristics that are different from other well-known image compression schemes such as JPEG and SPIHT. As a result, how to robustly transmit JPEG2000 bitstreams is an important research topic. In this paper, we apply our previous IL-ULP (improved layered unequal loss protection) scheme to transmit JPEG2000 coded images. We propose an accurate end-to-end distortion model to analyze the influence of different channel packets on the distortion of received images, where we consider the distortion contribution from each coding pass in each code-block. Our end-to-end analysis provides a feasible way to optimally allocate unequal FEC to a JPEG2000 bitstream according to given channel conditions. Experimental results demonstrate that our proposed IL-ULP can achieve good performance for transmission of JPEG2000 bitstreams.