OC--压缩图片到指定文件大小

/**

*  压缩图片到指定文件大小

*

*  @param image 目标图片

*  @param size  目标大小（最大值）

*

*  @return 返回的图片文件

*/

- (NSData *)compressOriginalImage:(UIImage *)image toMaxDataSizeKBytes:(CGFloat)size{

NSData * data = UIImageJPEGRepresentation(image, 1.0);

CGFloat dataKBytes = data.length/1000.0;

CGFloat maxQuality = 0.9f;

CGFloat lastData = dataKBytes;

while (dataKBytes > size && maxQuality > 0.01f) {

maxQuality = maxQuality - 0.01f;

data = UIImageJPEGRepresentation(image, maxQuality);

dataKBytes = data.length / 1000.0;

if (lastData == dataKBytes) {

break;

}else{

lastData = dataKBytes;

}

}