I used add and retrieve image in document directory simulator working perfect but device not working apps crash

        NSDateFormatter *format = [[NSDateFormatter alloc] init];
        [format setDateFormat:@"yyyyMMddHHmmss"];
        NSDate *now = [NSDate date];
        NSString *retStr = [format stringFromDate:now];
        
        NSString *anImageName = [NSString stringWithFormat:@"%@.png", retStr];
        NSString *anImagePath = [NSString stringWithFormat:@"%@/%@", dataPath, anImageName];
        NSData *anImageData = UIImagePNGRepresentation(image1);
        [anImageData writeToFile:anImagePath atomically:YES];

arrayOfImages = [[NSMutableArray alloc]init];
    
    NSString *stringPath = [NSString stringWithFormat:@"%@/brimages/",[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES)objectAtIndex:0]];
    
    NSArray *filePathsArray = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:stringPath error:nil];
    
    for(int i=0;i<[filePathsArray count];i++)
    {
        NSString *strFilePath = [filePathsArray objectAtIndex:i];
        if ([[strFilePath pathExtension] isEqualToString:@"jpg"] || [[strFilePath pathExtension] isEqualToString:@"png"] || [[strFilePath pathExtension] isEqualToString:@"PNG"])
        {
            NSString *imagePath = [stringPath stringByAppendingPathComponent:strFilePath];
            
            NSData *data = [NSData dataWithContentsOfFile:imagePath];
            if(data)
            {
                UIImage *image = [UIImage imageWithData:data];
                [arrayOfImages addObject:image];
            }
        }
    }