The Highlights feature worked as expected, singling out some 24 of the 64 images I uploaded from my trip to Death Valley.
This feature is automatic and needs no input from you. However, when you view a photo, it will display an icon reminding you that it has been enhanced, and lets you revert back to the original if you choose. Hitting the Edit button at the top takes you to Google's Creative Kit, which allows you to hand pick further edits and special effects for the photo.
The algorithm corrects overall tonal distribution, adds skin softening, removes red eye if necessary, sharpens and reduces noise, improves structure, corrects white balance, adds a vignette, and more.
This set of special effects is also enabled by default. As your images are uploaded into Google+, the photo algorithm chooses which effect to use and how it will handle the effect. For example, if photos were shot with overlapping edges, the utility automatically constructs a panorama. If there's a series of shots with similar backgrounds, the Mix feature will present you with a photobooth type collage. If you've taken a series of at least five photos in succession, Auto Awesome will stitch these photos together into a repeating short animation.
By merging differently-exposed images together and uploading them, Auto Awesome will create an HDR image. If you've taken group photos, Auto Awesome will choose the best shots of each person in your image and merge them into one optimal photo where everyone looks their best.
In practice, Auto Awesome is the glitchiest feature in the lot. Often, it did not recognize photos with overalpping borders as a pano, while varying exposures did not move it to HDR at all times. Sometimes it recognized a series of images as a GIF, other times not. It took a bit of paying around to see the results of that feature.
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