Number of Live Photos on iPhone Camera Rolls in the US
United States iPhone 6S and newer users have about 942 billion Live Photos on their camera rolls. This answer is an extremely rough estimation based on the following methodology and calculations.
Methodology and calculations
Number of iPhone 6s and newer models sold
There are no preexisting statistics regarding the number of Live Photos on iPhone camera rolls in the United States. I searched various mobile phone research reports, industry articles, and market studies
in an attempt to find precompiled information. Unfortunately, while there was some information on photos overall, there was nothing available about Live Photos in particular. Therefore, I triangulated a very rough estimate by following the suggested methodology in the request.
As of January 20, 2018, there have been 1.16 billion iPhones sold worldwide. Since there were 773.8 million sold prior to the announcement of the 6S and 6S Plus models, we can calculate that about 226,200,000 6S and 6S Plus iPhones have been sold (1,000,000,000 – 773,800,000). We can also calculate that there have been 160,000,000 7 and 7 Plus iPhones sold because after the release of the 7 and 7 Plus, the total phones sold jumped from 1 billion to 1.16 billion. So, 1.16 billion minus 1 billion equals 160 million.
According to Apple, 77.3 million iPhones were sold between October 1, 2017 and December 31, 2017, most of which would be iPhone 8 and iPhone X models, since they debuted in September and November 2017 respectively. Moreover, Apple expects to have sold 53 million more phones between January 1, 2018 and March 31, 2018. Therefore, we can estimate the total number of iPhone 8 and iPhone X models sold between October 1, 2017 and March 31, 2018 is 130.3 million (77.3 million + 53 million). Of course, not all iPhones sold at any given time are all one model, so this is a very rough estimate, but without pre-compiled sales data on each phone, we are unable to provide a closer approximation.
Using the above numbers, we can roughly estimate that there have been 516,500,000 iPhones sold globally that include the live photo feature (226,200,000 + 160,000,000 + 130,300,000 = 516,500,000).
Average number of photos taken
The average person takes 3,650 photos using phones equipped with cameras each year. iPhones equipped with the live photos feature have been on the market for 2.5 years. Therefore, the average iPhone user who purchased a 6S or 6S Plus iPhone has taken 9,125 pictures (3,650 x 2.5). The iPhone SE has been on the market for about two years. Therefore, the average iPhone SE user has taken 7,300 photos (3,650 x 2). The iPhone 7 and 7 Plus have been on the market for about 1.5 years. Therefore, the average iPhone 7 and 7 Plus user has taken 5,475 pictures (3,650 x 1.5). The iPhone 8 and 8 Plus have been on the market for about six months. Therefore, the average iPhone 8 and 8 Plus user has taken 1,825 pictures (3,650 x 0.5) The iPhone X has been on the market for about five months, so the average iPhone X user has taken 1,533 photos (3,650 x 0.42).
Certainly, many iPhone purchasers have upgraded from models that already include the live photo feature, so to determine an approximate average of photos on an iPhone user's 6S or newer phone, I calculated an average of the above numbers to be 5,052 photos (9,125 + 7,300 + 5,475 + 1,825 + 1,533 = 25,258 / 5 = 5,501.6 rounded to 5,502). Therefore, for the purposes of estimation, we can say that the average iPhone 6S or newer user has 5,052 photos on their camera rolls.
Unfortunately, despite extensive research into Apple user behaviors through case studies, research reports, and industry articles, I was unable to find the percentage of people who turn the live photo option off from the defaults setting of on. However, I was able to find research from User Interface Engineering that shows that 95% of people do not change their default settings on their digital devices, meaning only 5% change them (100-95). Although this study was from 2011, the percentage is still being used in current articles, so I believe this number has not significantly changed in the intervening years.
Therefore, we can assume that 95% of iPhone 6S and newer users have not turned off the Live Photos feature since "on" is the default setting. As such, we can also assume that 95% of the photos taken on iPhone models 6S and newer have been taken with Live Photos. Using this assumption, we can take 95% of the average number of photos an iPhone 6S or newer user has on their camera roll (5,052) to find an average number of Live Photos on a user's 6S or newer device: 4,799 (5,052 x 0.95).
We can then multiply the estimated number of 6S and newer iPhones that have been sold between the September 2015 debut of the 6S and 6S Plus phones by the average number of photos taken with the Live Photos feature to get the total number of Live Photos on iPhones on a global basis: 516,500,000 x 4,799 = 2,478,683,500,000 or 2.4 trillion photos.
Therefore, we can estimate that there are very roughly 2.4 trillion Live Photos on iPhone users' 6S or newer iPhones globally.
For the last calculation to determine the number of Live Photos on U.S. iPhone 6S or newer users' devices, I found that the international market makes up 62% of Apple's sales. Therefore, we can calculate that the U.S. makes up 38% of Apple's sales (100-62). We can then take 38% of the global estimation of Live Photos to get an approximate count of Live Photos on U.S. iPhone 6S or newer users: 2,478,683,500,000 x 0.38 = 941,899,730,000, which can be rounded to 942 billion.
As there is no pre-compiled figure available to state the number of Live Photos that exist on iPhone camera rolls in the US, this figure was triangulated. It can be roughly estimated that there are about 942 billion Live Photos on iPhone camera rolls in the United States. In addition, we also know that 95% of users of iPhones with the Live functionality are using it, and that the average person takes 3,650 photos using cameras on phones each year.