As you can see in the screenshots above, the image to the left is the original design where Google would place the image you selected against a black background. However as you can see in the image to the right, Google has changed the background color to a brighter color making it easier on the eyes.
Google also appears to have shifted the “X” button from the bottom right of the screen to the top right of the screen. Google has also introduced a sliding sheet at the bottom of the screen in which additional related images can be displayed as well, so if the image you’re viewing is not what you want, you can easily see the other results by scrolling down.
At the moment this testing appears to be very limited, according to the folks at Android Police. We’re not sure when Google plans to roll out this new design, if at all, but we’ll keep an eye out for it.