Magento Open Source, 1.9.x
Setting Up Dynamic Images

Dynamic images change when the corresponding swatch is clicked, and can be used on the product and product listing pages. The easiest way to understand this is to see how the products are set up.


Swatches

With this technique, each associated product must have an image that depicts the variation, even if the products are different sizes of the same color. These are the images that appear dynamically when the swatch is clicked. As with all swatch images, the dynamic image does not appear in the thumbnail gallery.