UicollectionView on scroll shows duplicate images

Question

I was using UICollectionView for Images grid appearance.while scrolling i found duplicate images appearing there. I was using NYXProgressiveImageView for downloading and displaying images. I Have implemented several methods found on search..

This is my code

- (MyCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
     MyCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CELL" forIndexPath:indexPath];
     if (cell == nil)
    {
        cell = [[MyCell alloc]init];
         [cell.imgv setImage:nil];

    }
     NSMutableDictionary *d=[[NSMutableDictionary alloc]initWithDictionary:[arrSubCatAndItems objectAtIndex:indexPath.item]];
         [cell.imgv setImage:nil];
     cell.imgv.cakeIndex=indexPath.item;
     cell.cellLabel.text = [d objectForKey:@"Name"];
     return cell;
}

Where as Mycell is Custom UICollectionViewCell class having ImageView and label init On scrolling iam loading visible images like this

 - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
      _isDragging=NO;
    if (!decelerate)
    {
        _isDragging=YES;
        [self loadimages];
    }
}
 - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
     CGPoint contentOffset = testscroll.contentOffset;
    CGRect  contentFrame  = testscroll.bounds;
    contentFrame.origin = contentOffset;
    if(!_isDragging)
     [self loadimages];
}

   -(void)loadimages
    {
              for (UICollectionViewCell *cell in [collectionview visibleCells]) {
            NSIndexPath *indexPath = [collectionview indexPathForCell:cell];

            MyCell *cell1 = (MyCell*)[collectionview cellForItemAtIndexPath:indexPath];
            NSMutableDictionary *d=[[NSMutableDictionary alloc]initWithDictionary:[arrSubCatAndItems objectAtIndex:indexPath.item]];

                      [cell1.imgv loadImageAtURL:[NSURL URLWithString:[[d objectForKey:@"ImageUrl"]stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];

          }
    }

Main problem if i scroll collection view on loading image in Imageview it is appearing in below cells

I don't Know where I am going wrong....New to UICollectionView...Please help me ..Tnx in advance