This is an extremely simple design effect. Probably image dependant to a certain degree, but try it out and see what you come up with.
Our image is brought to us by lock-e over at the StockExchange site HERE I have resized the image for this tutorial and darkened it a little.
Open the image and bring up your Rulers by going to View>Rulers – select the Single Row Marquee tool from the side toolbar, it is nestled with the rectangular marquee tool etc., and create a new blank layer. Make sure the f/ground is set to black – if you are using a dark image use white. And referencing the image below just click and the single row marquee will appear, Alt + Backspace to fill with black/white and then deselect.
Duplicate the marquee layer Ctrl + J or drag it to the create new layer icon at the bottom of the layers palette, grab the move tool ( V key on the keyboard) and then drag the duplicated line to where you want it. Continue doing this until you have all the lines as you want them. You might end up with something similar to mine – See image below. If you are happy with the lines merge the line layers into one layer.
Select the single column marquee tool and make vertical lines the same way you did the horizontal ones . see image
Once you are happy with lines, merge the vertical lines together and then merge the vertical and horizontal layers together. Go to View and uncheck rulers, rename the merged vertical and horizontal layers Grid Guide.
Create a new blank layer, make the f/ground colour white and choose the rectangular marquee tool (M on the keyboard) Go around the image and randomly select some of the squares (or whatever shape they may be), you could select two squares at the one time if you want. See my image below for my first selection.
Once you have that done, Alt + Backspace on the keyboard to fill the squares with white. Deselect, and then take the opacity of the layer down to whatever suits you, I did 25%. Turn the Grid Guide layer off to get an idea of what is going on. Continue randomly selecting areas, filling them with white and changing the layer opacity on new layers to build up the effect. Once you are happy, you can throw the Grid Guide layer away. You could also add some text to the image etc., and you may end up with something similar to the Final below, or you may end up with something much better because you’ll take more time making it 🙂 As an end note, you don’t have to use white in the squares, use whatever colours you want.