if i changed my apple id will all old photos under prior apple id be lost

Hi LESLIE K EX,

Welcome to the Apple Support Communities!

I understand that you would like to know if photos will be lost if you edit your Apple ID. Editing your Apple ID should not affect any of your photos. If you edit your Apple ID, you may need to sign out of the services it is currently signed into and sign in with the newly edited one. The article below has a list of services that can be used with an Apple ID.

Where can I use my Apple ID? - Apple Support

Best regards,

Joe

How do you want to change your Apple ID. If you change it entirely you will lose all photos in the My Photo Streams, Shared Streams, etc. Those photos that have been imported into your MBP iPhoto Library will remain.

You will also lose emails and messages if you change Apple ID accounts entirely.

If you only want to change the email address for the Apple ID account then you won't lose any of those items.