Individual Method:
In the Manage Photos screen, hover your mouse over a photo:
1. Click Edit on an image
2. Click Tag Product
3. Either search for your product or scroll through the list and check the products you want to tag
4. Click Select products
Bulk Method:
1. Click Bulk Selection in the top toolbar
2. Select the images you want to tag products in by clicking on them (this will select/highlight them)
3. Click Tag Products from the top toolbar
4. Select your products and click Select Products
Voila! Your Photo is now shoppable!