解决Ios加载大图时出JPEG Corrupt JPEG data: premature end of data segment错误，导致加载时卡的问题。

如题，有时开线程加载大图时，出如上错误（表象是某图有一部分是灰色区域），导致加载时卡。

比方说你做图片scrollview浏览时，滑动过程中创建大图，出如上错误会卡。

解决办法，用如下方法创建图，就很流畅了。

 

CGImageRef MyCreateThumbnailImageFromData (NSData * data, int imageSize)
{
    CGImageRef        myThumbnailImage = NULL;
    CGImageSourceRef  myImageSource;
    CFDictionaryRef   myOptions = NULL;
    CFStringRef       myKeys[3];
    CFTypeRef         myValues[3];
    CFNumberRef       thumbnailSize;
 
   // Create an image source from NSData; no options.
   myImageSource = CGImageSourceCreateWithData((CFDataRef)data,
                                               NULL);
   // Make sure the image source exists before continuing.
   if (myImageSource == NULL){
        fprintf(stderr, "Image source is NULL.");
        return  NULL;
   }
 
   // Package the integer as a  CFNumber object. Using CFTypes allows you
   // to more easily create the options dictionary later.
   thumbnailSize = CFNumberCreate(NULL, kCFNumberIntType, &imageSize);
 
   // Set up the thumbnail options.
   myKeys[0] = kCGImageSourceCreateThumbnailWithTransform;
   myValues[0] = (CFTypeRef)kCFBooleanTrue;
   myKeys[1] = kCGImageSourceCreateThumbnailFromImageIfAbsent;
   myValues[1] = (CFTypeRef)kCFBooleanTrue;
   myKeys[2] = kCGImageSourceThumbnailMaxPixelSize;
   myValues[2] = (CFTypeRef)thumbnailSize;
 
   myOptions = CFDictionaryCreate(NULL, (const void **) myKeys,
                   (const void **) myValues, 2,
                   &kCFTypeDictionaryKeyCallBacks,
                   & kCFTypeDictionaryValueCallBacks);
 
  // Create the thumbnail image using the specified options.
  myThumbnailImage = CGImageSourceCreateThumbnailAtIndex(myImageSource,
                                          0,
                                          myOptions);
  // Release the options dictionary and the image source
  // when you no longer need them.
  CFRelease(thumbnailSize);
  CFRelease(myOptions);
  CFRelease(myImageSource);
 
   // Make sure the thumbnail image exists before continuing.
   if (myThumbnailImage == NULL){
         fprintf(stderr, "Thumbnail image not created from image source.");
         return NULL;
   }
 
   return myThumbnailImage;
}