Flash memory based SmartMedia card is becoming increasingly popular as data storage for mobile consumer electronics. Since flash memory is an order of magnitude more expensive than magnetic disks, data compression can be effectively used in managing flash memory based storage systems. However, compressed data management in flash memory is challenging because it only supports page-based I/Os. For example, when the size of compressed data is smaller than the page size, internal fragmentation occurs and this degrades the effectiveness of compression seriously. In this paper, we developed a flash compression layer (FCL) for the SmartMedia card systems. FCL stores several small compressed pages into one physical page by using a write buffer. Based on prototype implementation and simulation studies, we show that the proposed system offers the storage of flash memory more than 140% of its original size and expands the write bandwidth significantly.