MyHeritage released their PhotoDater™ tool today. See their announcement on their blog.
I was among those that got a preview of the tool and have been using it to see how well it does as well as to answer some questions I had about a timeframe for a photo which some claim is of my 3rd great grandparents (born in 1803 and 1808 respectively). I have always felt that the photo was not them. The clothes, hairstyles date the picture to about 1890 and at that time they would be in their 80s. The folks in the picture do not appear to be in their 80s but closer to the 30/40 age range. A number of the ancestry trees have it attached to Daniel and Comfort Hatfield Pittman's profiles. The MyHeritage tool estimated the photo to have been from around 1890 with a high confidence level.
I knew the date of this picture of my Aunt Viola Cooke Agee. The PhotoDater™ was only off by one year. There are limitations of course to what it can do. This is going to be a very helpful tool to use in getting a quick idea of the time in which a picture was taken. See the blog post announcement from MyHeritage for full details.