为学校做的一个大图片展示方案。 实现非常大的图片在浏览器下浏览。 能够放大、缩小、最合适、原始大小浏览 鼠标拖动控制-For schools to do a big picture display program. Achieve very large picture in the browser under the browser. Can enlarge, narrow, the most appropriate and original drag the mouse to co