As a longtime iPhotos user, I’ve taken my sweet time getting to know the new Photos app in OS X. But I can tell you this much: It brings a few differences in the way it does stuff.
One of the new subtleties of the Mac’s Photos app is how it treats exporting your pictures. There are two ways to get your images out of the Photos app. One will give you a smaller file; the other will preserve the higher resolution of the original photo.
Here’s how to make sure you’re exporting your photos at the quality you want.