Adding Keywords to your Photos is an easy way to make them searchable, and easier to find. You can even search via Spotlight to find the images you’re looking for after you have attached keywords to them.
To do it, you’ll need to be using Preview to look at your photos. Under the tools menu select Get Info. Then click on the keywords tab, and then the Add button. This will add a field where you can enter your keywords. Seperate them by commas and you’re done.
Boom! Keyword searchable photos!