@implementation ImageSizeManager#define iphoneSize [[UIScreen mainScreen] bounds]#define newSizeWidth [[UIScreen mainScreen] bounds].size.width * 2.0#define newSizeHeight [[UIScreen mainScreen] bounds].size.height * 2.0//转换成大图片+(UIImage*)getMaxImageWithOldImage:(UIImage*)oldImage{    CGSize newSize = [self changeImage:oldImage.size andScale:2];    UIImage *newImage = [self imageWithImageSimple:oldImage scaledToSize:newSize];    return newImage;}//转换中图片+(UIImage*)getMidImageWithOldImage:(UIImage*)oldImage{    CGSize newSize = [self changeImage:oldImage.size andScale:4];    UIImage *newImage = [self imageWithImageSimple:oldImage scaledToSize:newSize];    return newImage;}//转换成小图片+(UIImage*)getSmallImageWithOldImage:(UIImage*)oldImage{    CGSize newSize = [self changeImage:oldImage.size andScale:8];    UIImage *newImage = [self imageWithImageSimple:oldImage scaledToSize:newSize];    return newImage;}+(CGSize)changeImage:(CGSize)size andScale:(float)scale{    float newWidth =  newSizeWidth/scale;    float newHeight = newSizeHeight/scale;    CGSize newSize;        if (size.width <=newWidth && size.height <=newHeight) {        return size;    }    if (size.width>newWidth || size.height >newHeight) {        if (size.width > size.height) {            //如果宽大，就把宽度缩小到,高按同比例缩放            newSize.width = newWidth;            newSize.height = (int) ((newWidth/size.width) * size.height);        }        else if(size.width < size.height)        {            newSize.height = newHeight;            newSize.width =(int) ((newHeight/size.height) * size.width);        }else//宽高相同        {            newSize.width = newWidth;            newSize.height = newWidth;        }    }    return newSize;}+ (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize{    UIGraphicsBeginImageContext(newSize);    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    NSData *data = UIImageJPEGRepresentation(newImage, 1.0);    DLog(@"长度:%d ",data.length);    DLog(@"长:%f 宽:%f",newImage.size.height,newImage.size.width);    return newImage;}