问ARC下的EXC_BAD_ACCESS内存错误

EN

-(NSMutableArray *)fetchImages:(NSInteger *)count {
//prepare URL request
NSString *urlString = [NSString stringWithFormat:@"http://foo.example.com/image?quantity=%@", count];

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString]];

//Perform request and get JSON as a NSData object
NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

//Parse the retrieved JSON to an NSArray
NSError *jsonParsingError = nil;
NSArray *imageFileData = [NSJSONSerialization JSONObjectWithData:response options:0 error:&jsonParsingError];

//Create an Array to store image names

NSMutableArray *imageFileNameArray;

//Iterate through the data
for(int i=0; i<[imageFileData count];i++)
{
    [imageFileNameArray addObject:[imageFileData objectAtIndex:i]];

}

return imageFileNameArray;

}