在手机应用程序开发中，常会需要加载一些图片，许多图片在手机屏幕上显示时会占用很大一块区域，

这时，调用ImageUtil中的方法可实现图片缩小或放大效果。获取适当大小的图片。-In the phone application development, often need to load some pictures, lots of pictures displayed on the phone screen will occupy a large area, then, call ImageUtil the way to achieve the effect to reduce or enlarge images. Obtain the appropriate size of the picture.