xtatiq requested a tutorial for this icon:
1. Choose any image. It’s best if there is decent contrast between light and dark. If it helps, crop it, resize it, whatever makes you most comfortable!
2. It's not really necessary here, but I made it very contrasty to show how increasing the brightness and contrast could make it so one could differentiate better.
3. PSP: "Freehand Selection", Point-to-Point.
PS: "Polygonal Lasso Tool." I don't recommend using the "Magnetic Lasso Tool" because it sometimes doesn't turn out as smooth.
Zero feathering. Outline all the dark parts. In this case, it’s the Doctor’s hair, eyebrows, tie, and suit.
Tip: PSP: Put the mode to "Add (Shift)." PS: Choose "Add to Selection." In both cases, you can select more than one thing at once.
4. Fill ‘em with black on a new layer.
5. Create a new layer under the black, fill that in with a color or texture, crop, resize, and you’re done!
All in all, it’s slightly different, but I think you get the idea :) It’s a rather simplified vector.
To change it up, you could also fill in the white parts, or even go as far as to fully vector it. You could throw different patterns and colors. In the stage where everything is selected, you could invert or inverse the selection, delete what's outside of it, and use what's left instead of black. You don't have to keep it as boring as I did ;)