Why Image Is Not Show When Images Are Stored In Nsmutablearray,If I Pass Image Name Then It Is Show Image Proper

for (int i = 0; i < [getArray count]; i++)
    {
        NSString *str=[[getArray objectAtIndex:i]valueForKey:@"rating"];
        UIImageView *img=[[UIImageView alloc]initWithFrame:CGRectMake(n*17, 100, 15, 30)];
        img.image=[UIImage imageNamed:str];
        [self.view addSubview:img];

        /* create label
      UILabel *label =[[UILabel alloc]initWithFrame:CGRectMake(n*17, 100, 15,30)];
         label.text = [[getArray objectAtIndex:i]valueForKey:@"rating"];
         label.font = [UIFont fontWithName:@"Times New Roman" size:30];
    
         label.textColor = [UIColor darkTextColor];
         label.textAlignment = NSTextAlignmentCenter;
         [self.view addSubview:label];
         n++; */
        n++;
    }