[iMore.com]

Don't let the name fool you, Photos for OS X also stores all your videos.

Whether you synced them from your iPhone or iPad using iCloud Photo Library or imported the manually, all your movie moments are right there alongside your images. Editing, however, is a different story. While you can trim videos in Photos for Mac, that's about all the editing you can do. For more, including titles, traditions, and other effects, you have to escalate to iMovie.

Full story from the iMore Blog...