I'm looking to clean up my iPhoto library and then move it to Photos. I have a bunch of older events that contain RAW images that I can safely convert to JPG prior to importing to Photos. The issue I have is I want to retain the event date i.e. the date the photos were shot. It seems if I export the RAW images from iPhoto to JPGs, the creation and modified dates are reset to today which means when it comes to importing, they will all have the same date. I want to be able to import these all back into iPhoto and remove the RAW images so I have an 'optimised' library that I can import in Photos. Is this possible or is there a better method that will effectively let me replace my RAW images with JPGs and retain the various events and dates?