adobe photoshop - Why is my grid not aligning properly?

I'm using Photoshop CS6 and for some reason the grid is not aligned 1 pixel by 1 pixel on my 20 pixel by 20 pixel image. I've tried everything and it still doesn't work. Any help would be appreciated.

here are my settings:

Guides,grids and slices

:

views:

p.s: I'm new to photoshop

Answer

I think I have the solution:

If you go to view -> show and remove the show grid, but choose the pixel grid, it should work (provided you have set the document to x number of pixels hight and width).