How to import image and match it with the grid system?

I am having a little bit of trouble importing my outline sketch image guide and make it match the blender unity system.
To make my self clear i am creating a simple game level in blender, i have created the outline of the rooms and corridors in the dimensions i want in photoshop ( Like a room has a dimension 10x6 then a corridor with dimension 4x2 ) and so on. It is very good in photoshop and i like it with all the dimensions that i used for it and not is the time to take into blender to through planes on top of this outline guide to create the floor.
My problem is that i am not being able to match the guide with the grids.
Any tips about how i make it work? So i just draw a plane and scale it to match the outline image to get the desired dimension automatically?
How to import image and match it with the grid system?

Just use the “Import Images as Planes” -addon. This will add a new plane to the scene proportional to your image and textured with your image. Then you can scale the plane to your needs.

The drawback of using pixel oriented pictures as reference is that you have to reconstruct the levels in blender from scratch as Blender is a vector oriented program. If you would construct your levels in a vetor oriented program like Illustrator or Inkscape you could import your levels as proportional 2D-vectors.

Thanks i will try this.