IPhoto won't delete photos?

Okay, so I have iPhoto on my school laptop. I'm trying to get rid of all my stuff before we have to turn them in next month. So, I went onto iPhoto and tried deleting my photos. Well, when I did, the photos stays there, but weren't clickable. So, I went to another album and came back. The photos were gone. I went to the trash and saw them there, so I emptied the trash. I decided to make sure they were deleted, so I quit iPhoto and opened it again. Well, when I opened it, my photos were all back where they had been. I've done this a number of times, and nothing's working. I can't even delete my slideshows and albums. I have plenty of room on my laptop - I only have a few NeoOffice doents, some photos, and some songs on iTunes. According to the Macintosh HD thing, I have 101.7 GB of space available, so I know that's not an issue. The weirdest thing is that I'm not even getting an error message. Can anyone help?