Removable apparatus with a plug-and-show function

A removable apparatus (25) with a plug-and-show function is applied to a wireless presentation system. The wireless presentation system includes a computer (23) and a wireless gateway (21). The computer (23) is capable of displaying plural presentation frames. The wireless gateway (21) provides ability in wireless network connection. When the removable apparatus (25) connects with the computer (23), the removable apparatus (25) can automatically analyze the difference region between the current presentation frame displaying in the computer (23) and the preceding presentation frame. The difference region is captured as an update image to be forwarded to the wireless gateway (21) through the computer. The wireless gateway (21) then reproduces a presentation frame the same as the current presentation frame in the computer (23) by integrating the update image with the preceding presentation frame. The reproduced presentation frame is then output to a display device (22) for further displaying.