— Reprogramming node software over-the-air is an essential requirement in many wireless sensor network applications due to the inaccessibility of the deployed sensor nodes. Transmitting whole software images consumes a high amount of energy in proportion to updates especially when they are small in size. Incremental updates have addressed this, however introduce the potential of a sensor node becoming out of sync when it misses an update. In this paper we present a dynamic size distributed program image cache that provides increased efficiency in reprogramming out of sync nodes and multi-purpose wireless sensor networks.