Sometimes you need create grids in a picture. Here I describe a method to create grids in Photoshop that is very easy.

1. Create a new image, type in the height and width of the square you wish to have, set the background to transparent. Zoom in or out to see the full image

2. Select -> All , or Ctrl-A. this places a rectangle marquee around the entire square.

3. next we go Edit -> Stroke. Select a pixel width, color, location (inside-center-outside, don't pick outside right now)for your grid lines

4. We now go Edit -> Define Pattern give your new grid pattern a name.

5. To create the pattern, select the area, object, image then Edit -> Fill -> Pattern and select Custom Pattern, your grids should be the last icon on the list and may only look like a transparent area.

That is it! Now you have your grids created for the image.