people would stay on the president's twitter feed much longer if he included images
doesn't really matter what
twitter is a visual experience and most - nearly all - of the president's tweets lack any images or video
people under 50 and definitely under 30 will stop reading sooner when their are not images or SHORT video clips than they would if there were something other than text
consider the cost benefit of 500 tweets a day and the average viewer stays on the thread < 5 minutes, versus 100 tweets a day and the average viewer stays on the thread for 15 minutes
which better accomplished your goals?