why have the same V before and after resistor?
The resistor is only connected to the negative rail.  The other side of resistor, which is on the central board area (I have no idea what that area is called) is not connected to anything.

On a bread board, the power rails (the strips of 2 that run vertically) are connected.  On the central plains, the strips are connected horizontally.  There does not appear to be a connection between the red jumper and the resistor.

Here's a bit more information on exactly what makes up a bread board:
https://learn.sparkfun.com/tutorials/how-to-use-a-breadboard