What should i do with iPhoto after upgrade to Photos.

No - it is advisable to keep the iPhoto library as you might need it or want it in the future - and deleting it will save very little space as the original photos and teh previews are not duplicated but linked with hard links - Photos saves disk space by sharing images with your iPhoto or Aperture libraries - Apple Support

You can delete it but until you are 125% sure you do not need it it is best to keep it - and if you delete it be sure you have a good backup

LN

I have a thread similar to this. I prematurely deleted the iPhoto library and made a copy of the Photo library, and moved it to my new MBP to see if all my photos were contained in there - and they were! Looking back, I kind of regret deleting the iPhoto library and would have instead simply moved it to an external HD as a just-in-case file. They were the same size (pretty much), so I figured all the photos were in both files (again, I probably should have thought twice about assuming things like this). Basically, I'm 99% sure it's ok to delete/remove from your computer, but I would keep it on an extra HD... just-in-case.

I do have questions for you, though. Have you upgraded to El Capitan? If yes, is the iPhoto app still on your computer?

I've also read that deleting the iPhoto library will recover little space. However, I don't understand how that can be if the iPhoto library is the exact same size as the new Photo library. Like I said in my previous post, I moved the Photo library to a new computer, and all the photos/videos were there - which tells me that the Photo library has no connection to the iPhoto library whatsoever (at least not anymore). If the Photo library relied on the iPhoto library via the hard links, moving the Photo library (alone) onto a new computer would not have worked.

Am I getting this right?

Yes and yes - but again ThreadJacking is confusing for you, the volunteers, the OP and future readers - please start new threads with new issues and new questions - Writing an effective Apple Support Communities question

specifically

Ask your own question. Don't tag a new question on to someone else's. No two Macs remain completely identical after they leave the factory, so it's very likely your problem is quite different than that described by the originator of a thread, even if your symptoms are exactly the same.

Tacking on "me too" replies to someone else's question is an annoying distraction that hinders others from addressing the originator's concern. It's analogous to barging into a physician's examining room while another patient is being treated, and saying "hey, I've got the same problem". If you really are experiencing the exact same problem, merely subscribing to that thread by clicking the "Follow" link (checkmark icon) is sufficient to receive email alerts whenever someone replies to it. You can wait for a solution to be posted and for its originator to mark it "solved", but it's better to ask your own question so that you can receive the individual attention you deserve. This is the best way to receive timely, relevant, and accurate replies to your question.

LN

er1c15 wrote:

I've also read that deleting the iPhoto library will recover little space. However, I don't understand how that can be if the iPhoto library is the exact same size as the new Photo library. Like I said in my previous post, I moved the Photo library to a new computer, and all the photos/videos were there - which tells me that the Photo library has no connection to the iPhoto library whatsoever (at least not anymore). If the Photo library relied on the iPhoto library via the hard links, moving the Photo library (alone) onto a new computer would not have worked.

Am I getting this right?

no

deleting it will save very little space as the original photos and teh previews are not duplicated but linked with hard links - Photos saves disk space by sharing images with your iPhoto or Aperture libraries - Apple Support

When you moved it then duplicates were created since you broke the hard links - no duplicates were created by the migration

and you have not previously posted in this thread - ThreadJacking with different issues is confusing to everyone

LN

Does this mean... if I had a 64gb HD and my Photo library was 35gb, I would be able to transfer BOTH the iPhoto and Photo libraries to that HD without a message saying I don't have enough space?

Scott, after reading everything over and over, my advice is this (and since you welcomed other thoughts on the issue, I hope you don't mind)... move your iPhoto library onto an external HD. Open Photos. Is everything there? If yes, just keep the iPhoto library on your external HD. If no, move it back.

Not sure what LarryHN is on about threadjacking since I think everything I said pertained to your original inquiry. I guess no one is supposed to contribute to a conversation unless they know the 100% correct answer to what is being asked? oh well.

ThreadJacking is about asking non repeated questions thereby confusing a thread which is exactly what you are doing - you gave no answers but ask several non related questions all of which demonstrate your lack of understanding on how Photos works

And your advice to move the library to an external drive is poor advice since you do not have adequate information to make such a suggestion and you do not have enough knowledge to provide the parameters for doing that and explaining the requirements

And one is welcome to provide tested answers - posting non related questions and totally speculative guesses that do not address the OP's question and could be destructive to their photos is bad

Hopefully the OP will see that you have only answered one question successfully and ignore your bad advice

LN

After migrating all the pics in Iphoto to photos, I deleted iphotos library and freed up the space that they were taking. I now have more free space showing on my drive. This seems contrary to the information on this thread.