Photoshop Tutorials: Turn A Photo Into A Collage Of Squares

Step 3: Drag Out A Square Selection Around Part Of The Image

I'm going to click back on the copy of my Background layer, "Layer 1", in the Layers palette to select it. Then I'm going to grab my Rectangular Marquee tool from the Tools palette:

I could also press M on my keyboard to quickly select it. Then, with the Rectangular Marquee tool in hand and "Layer 1" selected in the Layers palette, I'm going to drag out a square-shaped selection inside the image. I'll drag out a square around the boy's face on the right:

In order to constrain the selection to a perfect square, hold down Shift as you drag.

Step 4: Add A Layer Mask

Once you have your square-shaped selection, and again making sure that "Layer 1" is selected in the Layers palette, click on the Add A Layer Mask icon at the bottom of the Layers palette:

This will add a layer mask to "Layer 1", and because I had an area of the image selected when I clicked the "Add A Layer Mask" icon, Photoshop will use that selection to create the mask, meaning that only the area of the image that was inside the selection - the boy's face - will remain visible in the Document Window. The rest of the image will be hidden from view, revealing the white-filled layer below it:

Step 5: Unlink The Layer Mask From The Layer Contents

If we look at our Layers palette once again, we can see the layer mask that's been added to "Layer 1". The mask is filled with black, except for the small square area that's white, which is the area around the boy's face that's showing in the Document Window. If you look closely, you'll also see a small link icon between the layer thumbnail and the mask thumbnail:

When that link icon is visible, it means that the contents of the layer (the image) and the layer mask are, well, linked. If you move one, you move them both. That's not what we want. We want to be able to move the mask without moving the image. In order to do that, all we have to do is click on that link icon, which will cause it to disappear, at which point the layer mask can be moved independently of the layer contents. I'm going to click on the link icon to remove it: