How do I delete a photo set, or an individual photo from a set?

To delete photos in Zalongo you must be the user that uploaded the file. If you are that user, scroll to the bottom of the picture page where you will see some options. 

One option is 'delete'. Click it and confirm.

To delete a set, you must first delete all photos from that set. Then make sure you are clicked into that album. One of the options that is available is 'delete'. Click it and confirm.