One of the pleasures of using a smartphone to take a photo is that it’s (most likely) embedded with GPS data. This is especially handy for applications — like iPhoto — that allow you to search for photos by location. But if you use a stand-alone camera for better quality pictures, you probably aren’t getting any location data. iPhoto will allow you to manually add an address, but that’s time consuming if you have a lot of photos (which you probably do), not to mention not very helpful if the photo was taken out in the woods or on the beach or something.
So here’s what I do…
Wherever I take pictures with my camera, I also take one photo with my iPhone. It doesn’t have to be a good photo. You just need the GPS data. For example, here’s a photo of my shoe taken in my home office.
And here’s a photo of me in home office, taken on a much better camera that lacks built-in GPS.
To grab the location data, I just “right click” on the shoe photo (or “control click” if you don’t have a right click spot on your mouse/trackpad) and select “copy.”

Then I select the photo(s) I want to give a location, go up to the EDIT menu,and select “PASTE LOCATION.” (Note: You can select more than one photo by pressing the COMMAND key as you click on them.)
And that’s it. Now your “good” photo (or photos) will have the GPS data.
I did this on our honeymoon to Italy, easily giving hundreds and hundreds of photos location data that didn’t otherwise have them.