Go from this:
to
I first took
this picture; resized, cropped, and sharpened it.
Now it's time to desaturate the picture (shift+h)
->
I don't like how it looks, so I go to brightness/contrast (shift+b) and decrease the brightness to -10 and increase contrast to 30.
->
Now it's time to burn. I floodfilled a new layer with #4F311F, set to burn 30.
->
Text is the only thing missing so I use this brush made by ? (please tell me if you know).
Other icons made this way: