What I am saying is for a pic to be updated as SB pic, you need to post a single picture separately. If you have multiple pictures of SB or Building, you can select one pic which is best of the lot and upload it SINGLY. So suppose you have taken 4 pics, select the best and post it SINGLY. The rest 3 pics can be uploaded using "Reply" option together. So 1 pic in main post and 3 pics together in sub-post # 1. Hope you got it.