It looks like Google is testing a new look for the drop down to select a color in the shopping panel. Tauqeer Aziz shared a screen shot of him bringing up an iPhone in the Google web search results and when you click on the drop down, it shows the colors and a photo of the phone in those colors.

The original version just lists the colors but does not show an image of the color options.

Here is the test version from Tauqeer Aziz on Twitter:

Here is what I see right now:

It is a tiny change but it makes a difference to shoppers I believe.

Forum discussion at Twitter.