The resource limitation of mobile commerce systems cause the problem that the existing image processing software based on the centralized computing mode had difficulty in running in mobile commerce systems. This paper gives a solution for the problem by adopting web service-based image processing approach. The solution reduces the resource consumption of mobile commerce systems by distributing image processing tasks to service providers, service registry centers and service requesters. Furthermore, a web service discovery algorithm called WBSD is presented. Service providers adopt the WBSD to provide efficient services and increase image processing speed. Compared with traditional methods of image processing, Web service-based image processing method has the advantages of loose coupling and component oriented and can take full advantage of the computing resources in heterogeneous network. Thus web service-based image processing approach can effectively solve the resource bottle-neck that traditional image processing software had.