UPDATED Several Times Since first posted on January 28, 2016: Here are some screen shots from CNN and ABC of Hillary Clinton and Bernie Sanders giving live speeches. I then used a computer program to estimate the ages of the candidates. The computer program provides fairly accurate estimates of their ages. Both pictures is be fairly accurate in estimating their ages.
The weird thing occurs when you look at the stock pictures that the different networks use for the candidates. Below are the pictures from CNN, Fox News, MSNBC, CBS News, ABC News, and NBC News. In virtually all of them it is clear that Hillary Clinton's picture has been photo shopped so that she has a plastic type look and she appears to be much younger than she is. Some of these pictures of Hillary Clinton are clearly airbrushed, particularly CNN and MSNBC. While Hillary Clinton's campaign might have provided some of the pictures, many are clearly taken from these news programs stock footage. But all the pictures of Hillary Clinton show her decades younger than her true age. By contrast, half of Bernie Sanders pictures indicate that he is older than 74. For Martin O'Malley, 3/4ths of his pictures show that he is older than his true age of 53.
Across the news show pictures shown below, Hillary Clinton's average estimated age is 38, about 30 years younger than her actual age. Even eliminating CNN's picture where she appears to be only 29 years old, the average for the other five news organizations puts her at 28 years younger than her actual age. The pictures used for the other candidates create an impression that the candidates are much closer to their actual ages. Bernie Sanders' average estimated age is 71.3, about 3 years younger than his actual age. Martin O'Malley's average estimated age is 58, five years older than his actual age.
To put it differently, if you relied on the stock photos provided by news organizations, Hillary is by far the youngest Democrat in the race, 20 years younger than O'Malley and 33 years younger than Sanders.
Even if wants to restrict the analysis to the polling type line up that I have for four of the news organizations, the results would have implied that Hillary Clinton was now 37.8 years younger than Sanders (Hillary Clinton estimated age of 39 and Bernie Sanders 76.8) and 20 years younger than O'Malley. So as to reduce arbitrariness and facilitate comparisons where pictures are picked for pure news shows, I have limited myself to still shots where at least two of the candidates are pictured next to each other.
Note that there are other oddities with these pictures. For example, for CBS compare the smiling Clinton to open mouthed Sanders or O'Malley. I have no idea whether this makes her look more sympathetic and friendly, but it is interesting just to note that almost all the other networks have pictures for these polling results of all the candidates smiling.
The point of the two pictures of Clinton at the top and the one at the bottom show that there are lots of stock pictures that the media could have picked that would have treated Clinton similar to her Democratic opponents.
More pictures from the AP on June 7th. This picture for Hillary is not as extreme as the ones shown above, but while the picture makes Hillary look younger than she is, the picture for Trump makes him look older. Just looking at these two pictures seems to me that the one for Hillary is much more positive and happy compared to the one for Trump.
Here are two pictures on June 7th from Fox News.
I have also examined some pictures of Carly Fiorina for a comparison and the computer accurately predicts her age.
Here are some additional pictures to help gauge the accuracy of the How-Old.net program as well provide additional information on how Hillary is treated. Megyn Kelly is 45, but she looks like she is 47. Lester Holt is 58, but he looks 55. Amazingly, at least to me, Megyn Kelly looks older than Hillary Clinton's still pictures used with the polling numbers.