Duplicate Photos Due to Folder

I migrated from an old mac, same version of iPhoto. However, I didnt use the migration assistant. I simply restored the files I wanted from a backup I had made of my old computer using TimeMachine.

My current iPhoto Library is huge, and Im sure its because of duplicate photos. I was snooping around today and found that iPhoto has an event called PreBautizo which is I name I obviously created way back. In that event it has 350 photos. Then in an event called Pictures, it has 338 photos (because i started deleting a few unwanted pictures from it a couple of days ago). Ive checked and they are all the same pictures in both of these folders.

Then I checked my user/Pictures folder and found that there is a specific folder called PreBautizo. So I need advice on this:

Obviously iPhoto imported the previous library with that PreBautizo event already in it. And it may have searched my drive for more pics and found the PreBautizo folder and added it as a complete event? Im not sure. What I want to know is, which folder should I erase; PreBautizo or Pictures?

That will depend on how iPhoto actually works. When I take pics with my iPhone, i connect it and it downloads the new pics to iPhoto and creates those events for me, which is cool. But since in my user/Pictures folder I have both the PreBautizo folder, could it be that if I delete that EVENT, iPhoto will keep creating it when it finds that specific folder in my user/Pictures folder?