• Start Adobe Photoshop and make 288x209 px photo, 72 px/inch resolution.
• Import (place) the "zoo" design into it, download here or draw anything you want.
  The image should look like this :

• Duplicate image (we'll need it later).
• Go back to the original copy, choose layer 1 (zoo) and go to Filter > Blur > Gaussian Blur.
• Set the Radius to 3.2 pixels and click OK.
• Now flatten image.

• Go to Filter > Pixelate > Color Halftone, set the Maximum Radius to 5 pixels.
• Set Chanels 1,2,3,4 values to 0 (zero), and click OK.

• Click Magic Wand tool, set the Tolerance to 10, uncheck Contiguous option, and select.
• Invert your selection then drag it into the image copy you've already made.

• Now you have 2 layers: the original "zoo" and the last one with proportional circles effect.
• Use the Styles palette to apply some cool effects :

• Well, now you got it. Great!.