Apple Photos Automatically Reducing Size

I noticed something odd today, and can't seem to find any solution. When my larger sized photos from my DSLR are put into Apple's new Photos app, if I am to drag a copy back out and save it back to the computer, it automatically reduces the size of the photo by nearly half, reducing the quality in the process. I tested this further with smaller sized photos from my iPhone, and it doesn't do that for them. I also tested if it's anything I save to the computer by texting a large 9.6mb sized photo and then saving it to desktop, and that wasn't reduced either; it's just when I move it from the Photos app.

Any help??