Visualising downwash over a finite wing The downwash is caused due to higher pressure below the wing than above it (for a positive lift generating wing that is). What I am not able to understand is how would the flow be in a gross sense? Will the flow move bottom to up around the wing tips and move top to bottom along leading and trailing edge? I thought of this because it is the only way I am able to justify that downwash induces a negative velocity component which decreases the angle of attack that the wing sees at the leading edge. 

But can’t the air also move bottom to up along leading or trailing edge? To me, at leading edge it seems unlikely based on intuition because of the air upstream constantly trying to direct the air ahead but at trailing edge it seems more likely. 

So what is the correct visualisation of downwash over a finite wing?
Downwash is a misleading concept when discussing airfoil lift. Instead, just focus on the pressure distribution around the airfoil.

If I understand your confusion correctly, you are picturing, correctly, that there is an overall low pressure on top and an overall high pressure on the bottom, then why isn't air flowing from high pressure to low pressure?

This will indeed be the case, if there is no airflow. What you are missing is that, the static pressure distribution is caused directly by the airflow around the airfoil. The distribution is steady-state, because the combination of dynamic pressure and static pressure resists further changes; it's at an equilibrium.