In this paper, we propose a simple and effective scheme for screen image scaling, targeting at real-time applications like remote desktop and screen sharing. To balance visual quality and complexity, we build our scheme upon bilinear interpolation and devise a content adaptive post-processing method. Our scheme keeps the text/graphics regions of screen images as sharp as the original while avoiding magnifying noise and artifacts in the picture regions. Further, the involved operations are quite suitable for hardware acceleration. When implemented on commodity GPUs, our scheme achieves a frame rate more than 300 fps, which is fast enough for practical use.