how do I merge my Photos with IPhoto

Why do you want to delete iPhoto? the application does not need that much storage, but is very difficult to get back. You may need it to repair older iPhoto Libraries, if you have to restore a library from a backup.

At least keep a copy of iPhoto on your backup drive.

Just realized that I am running Photos and IPhoto on my IMac how do I merge these two? or just delete the old app?

How did you migrate from iPhoto to Photos?

Did you import photos to iPhoto after you migrated your iPhoto Library to Photos for Mac? Any changes, imports, edit you make in one of the applications will not be visible in the other application.

There are no tools to merge iPhoto Libraries into Photos Libraries. Export all photos from the iPhoto Library that you imported after you created the Photos Library. Then import those photos to Photos.

After that, make a backup copy of your iPhoto Library and you can remove it from your system drive.

You do nothing with the Apps

Your photos are in the iPhoto library and the Photos library - unless you have been running both apps and importing photos to both then the one you are using has all of your photos in it and there is no advantage to doing anything with the old library until at least three months after migrating - the space savings will be minimual

LN