(iPhone)怎样从photo album中获取所有图片 “＊＊＊＊ONE＊＊＊＊＊” －－－》 怎样从CGImage 转换成 NSData?

1:
- (NSData *)imageData {
    ALAssetRepresentation *assetRep = [self.asset defaultRepresentation];
     
    NSUInteger size = [assetRep size];
    uint8_t *buff = malloc(size);
     
    NSError *err = nil;
    NSUInteger gotByteCount = [assetRep getBytes:buff fromOffset:0 length:size error:&err];
     
    if (gotByteCount) {
        if (err) {
            NSLog(@"!!! Error reading asset: %@", [err localizedDescription]);
            [err release];
            free(buff);
            return nil;
        }
    }
     
    return [NSData dataWithBytesNoCopy:buff length:size freeWhenDone:YES];
}
2:当然我们还可以使用
     UIImagePNGRepresentation(UIImage *image)。
     UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality)。