Above: A free-to-use stock photo tagged with the search term "searching". Credit: Gratisography.
Something in the order of one billion new photos are uploaded to Instagram each day. That is a lot of photos for, say, a social historian, to engage with. The scale of the task facing the social historian interested in photo-visual resources can be considered in terms of time available for research.
Let us say that a social historian's entire working life is fifty years (they begin work at age twenty and work to age seventy). In order to gain an uncompromised awareness of one day's postings to Instagram (a notional one billion photos) then the the reviewer might expect to skip fast though the images, dwelling on each one for only two seconds. Completing this process (a review of one day's postings), for all of the given image study material, would take the researcher 124 years (assuming 12 hour working days; and seven-day's-a-week without holidays for all of working life).
Obviously, before the researcher began this daunting process, he or she would have to find a way of capturing all the material and keeping a copy of it--with this in itself a rather fazing prospect since in theory the permission of each end-user would be needed in writing (as some sort of release document) in order to be sure of not breaching any privacy laws.
One conclusion that can be drawn from the above is the likelihood that researchers of such material will increasingly tend to rely on indicative samples, using hash-tag-based searching, for instance, rather than gaining a definitive overview of photo-making activity in any given epoch.
(29 March 2018)
Appendix - from Study.com
There are 60 seconds in 1 minute, and 60 minutes in one hour. This means there are 3600 seconds in one hour. There are 24 hours in one day, so 24 x 3600 will tell us how many seconds are in one day. There are 86400 seconds in one day. Since there are about 365 days in one year, multiply 365 x 86400 to find the number of seconds in one year. This equals 31536000, which is the number of seconds in one year. To find out how many years is equivalent to 1 billion seconds, divide 1 billion by 31536000. The answer is 31.70979198376. One billion seconds is equivalent to 31.71 years.