我是一个搬运工，只会copy，转载转载转载：https://blog.csdn.net/benyoulai5/article/details/50462586

4.0.3版本时，可以改    

[SDImageCache sharedImageCache].config.shouldDecompressImages = NO;    [SDWebImageDownloader sharedDownloader].shouldDecompressImages = NO;

5.0.6版本时，以上属性不见了，看此链接https://blog.csdn.net/benyoulai5/article/details/50462586，

SDImageIOCoder.m 中

- (UIImage*)decodedImageWithData:(NSData*)dataoptions:(nullableSDImageCoderOptions*)options {

    if(!data) {

        returnnil;

    }

    CGFloatscale =1;

    NSNumber*scaleFactor = options[SDImageCoderDecodeScaleFactor];

    if(scaleFactor !=nil) {

        scale =MAX([scaleFactor doubleValue],1) ;

    }

    UIImage*image = [[UIImagealloc]initWithData:datascale:scale];

    if(data.length/1024>128) {

        image = [selfcompressImageWith:image];

    }

    image.sd_imageFormat = [NSData sd_imageFormatForImageData:data];

    returnimage;

}

-(UIImage *)compressImageWith:(UIImage *)image

{

    floatimageWidth = image.size.width;

    floatimageHeight = image.size.height;

    floatwidth =640;

    floatheight = image.size.height/(image.size.width/width);

    floatwidthScale = imageWidth /width;

    floatheightScale = imageHeight /height;

    // 创建一个bitmap的context

    // 并把它设置成为当前正在使用的context

    UIGraphicsBeginImageContext(CGSizeMake(width, height));

    if(widthScale > heightScale) {

        [imagedrawInRect:CGRectMake(0,0, imageWidth /heightScale , height)];

    }

    else{

        [imagedrawInRect:CGRectMake(0,0, width , imageHeight /widthScale)];

    }

    // 从当前context中创建一个改变大小后的图片

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    // 使当前的context出堆栈

    UIGraphicsEndImageContext();

    returnnewImage;

}