Actually latest is not a version - you would be shocked at what people claim is the latest - it helps to have the version number - and again we need to know how you are deleting photos and from where
since something is not working we need the details requested to help figure out what is going wrong
What version of iphoto and of the OS? Where are these photos reappearing - in MyPhotoStream, shared PhotoStreams or events? Exactly step by step how are you deleting them and from where? What has changed since it worked correctly?
The correct way to delete photos is to select them in an event and press the delete key (or drag to the iphoto trash) and then empty th epithet trash ad the system trash - do not merge or organize events before emptying the iPhoto trash
LN