Imo this picture is a piece of a puzzle that someone who suspects a relative, friend, coworker, neighbor etc needed to start putting things together..the voice was another corner piece of the puzzle, the clothing another....it's faceless and useless to you because you don't know him and don't suspect anyone in your life. These are all triggers for the people that DO know him. The rest of the general public could never ever see what has been released and recognize it as someone next to them in the grocery store. I'm fairly certain LE knows that.
There is a reason they have only released what they have at this juncture. It's not their job to satisfy curiosity, it's their job to keep the integrity of their case intact while still trying to utilize the media and general populations of the entire country to help.
The sheer amount of tips being generated from this snippet is unreal honestly and I'm sure none except for maybe two will pan out. But all these details everyone is begging for are the same details that allows them to sift thru the never ending sand the waves keep pushing in....to get to those one or two tips while the waves keep crashing must be utterly exhausting and disheartening, but they keep pushing thru hour after hour and minute after minute. Let's have some faith.
These cases can take week, months, years and maybe never. Take a look in other threads for missing, Unidentified people. Help where you can.
I think everything that can possibly be dissected has been at this point and so we wait. LE will most likely update again soon and then we dissect again.