I have a group shot from your link. The URL at the top points to the position within an album. But because everyone can choose the sequence of display, this gets stored in their cookie or profile, they will get to the image that is in that position in their sequence.
You can try changing the sequence, the options are Title, Filename, Date or Position and then you will see a different image for your link.
The link that is given below the image represents the actual database location of your image and thus always returns the same picture instead of one relative to the sequence within an album.
Hope that is clear :shock: might not be 100% accurate but it is how I observe it to work.