iOS 压缩UIimage图片
//压缩图片方法
- (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize{
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}