For about a year now I've been using the Photos app my MacBook Pro (OS X El Capitan 10.11.5). Before Photos, I used iPhoto for a couple of years. I only started using Photos once it shipped with newer OS X installations.
I'm out of space and, looking at my disk usage, I see that iPhoto is consuming almost 80 while Photos is consuming 15 gigs. The Optimize Mac Storage setting is enabled in Photos. That could mean it is only downloading 15 gigs worth of media, and that would explain the usage difference between iPhoto and Photos. It could also be that not all photos from iPhoto have made it to the cloud. Is that likely? I think all media should be imported entirely once I installed Photos, but I don't want to risk it.
Can I safely remove iPhoto from my computer or its library at least?