Blending Icons to background

[artreite]

What are the little gray squares that blend images to whatever background they are on?

see example image:

[Norman Sanders · Accepted solution]

I believe you are referring to the pattern that denotes a transparent area.    

For example, if the logo pictured is on a white background and you want the logo's surround and the inner g+ to be transparent so that they can be superimposed on another image, choose the Magic Wand with Contiguous unchecked in the Options bar and click in the white area. If there is a lock on the layer, trash it. Then hit Delete.

Another option: since the logo is black and is on a white background, simply placing the layer over an image layer and set its Blending mode to Multiply.