In your Gallery/Moderate Gallery view, mouse over a photo
- Click on the 'Edit Post' button
- Click the 'Tag Products' button
- Start typing the displayed Product's Title
- From the drop-down, select the corresponding Product
- Click 'Select'
Voila! Your Photo is now shoppable!
You also might want to learn How to tag multiple products in one image and 'Hotspot' them.