IOS 压缩图片到指定大小kb

.h

#import 

@interface UIImage (WLTScaleImage)
+(UIImage *)scaleImage:(UIImage *)image toKb:(NSInteger)kb;

@end

.m

#import "UIImage+WLTScaleImage.h"

@implementation UIImage (WLTScaleImage)

+(UIImage *)scaleImage:(UIImage *)image toKb:(NSInteger)kb{

    if (!image) {
        return image;
    }
    if (kb<1) {
        return image;
    }

    kb*=1024;



    CGFloat compression = 0.9f;
    CGFloat maxCompression = 0.1f;
    NSData *imageData = UIImageJPEGRepresentation(image, compression);
    while ([imageData length] > kb && compression > maxCompression) {
        compression -= 0.1;
        imageData = UIImageJPEGRepresentation(image, compression);
    }
     NSLog(@"当前大小:%fkb",(float)[imageData length]/1024.0f);
    UIImage *compressedImage = [UIImage imageWithData:imageData];
    return compressedImage;



}
@end