If you had just looked at this post without reading this message, would you have seen one image, or known that there are ten images to scroll through? Many seem confused by the AU interface when several images attached.
Not sure if it makes a difference what device you use but on a laptop its clear. Unless the bottom of the photo is white and you don't sweep your mouse across the photo to expose the bars with arrows on each side. It's hard to miss. Not sure how it presents on a phone though.