Maybe it's changed over time since this was posted, but right now the top result for "tank man" on DDG is

https://en.wikipedia.org/wiki/Tank_Man

and though the image searches do show a bunch of other things (all including "tank man" in the name at least), they _do_ also include the iconic photo at least once:

http://www.maryscullyreports.com/wp-content/uploads/2017/06/...

which I did not see in the bing results...