Well, because it was requested, I decided to make a tut. My first, so go easy on me!
So you want to go from this to ?
Well, the pic I'm using I've already cropped to a perfect square. NOTE THAT I HAVE NOT RESIZED IT TO 100x100. But, yes, the first thing to do is to make it a good, pretty square (mine is 567x567, for any who cares.)
Then, make a new layer, and on that layer, take a relatively thick brush (I'm using it at 23pt) at 100% hardness and outline your figure. It doesn't have to be perfect, just make a satisfactory outline.
Then - you won't believe me - set the layer that has the outline on it to exclusion. This should show you wherever your line is overlapping the figure. ((If it doesn't do that very well, try it on Overlay, or even Color burn.))
So now it looks really scary. Just be glad it's not going to look like this when you're done.
See those white bits on Erik's shoulder and in Christine's hair? That's where my line overlaps the figures. So, I simply take my handy-dandy eraser and erase those bits. I then set the layer with the outline back to normal, and do my little perfecting bits.
NOW I resize the image to 100x100 and sharpen ONLY THE BACKGROUND LAYER, NOT THE LAYER WITH THE OUTLINE. Do whatever cool and uberspiffy sharpening trick you've mastered, yes - but only to the background layer! I cannot stress that enough. And also, do not flatten the image, merge the layers, or reduce your layer count in any way, shape or form. It's not cool.
Desaturate the base. Now it's all greyish, and not really black and white, so up the contrast a little (Image>Adjustments>Brightness/Contrast).
NOW it's starting to look like it might turn into something, ne? ((Agree with me. xD))
I take this texture, made by me, _ashenicons, and paste it underneath the layer with the outline. it looks like this:
Very convienient! The outline is telling me exactly where to erase! So I do, erasing everything inside the outline. It also gives me a certain margin of error.
Now I think that the background's a little harsh, so I take this light texture by awmp...
... and, after setting it to hard light, opacity 100%, I treat it like I did the other texture, erasing what covers Erik and Christine, using the outline as a guide.
I make a new layer on top of everything, and on this sparklingly new layer, I put a THICK border, 6pt or so. Then I take out my good friend Mr eraser and erase wherever the border is overlapping Christine and Erik. In a sense, I'm making it so that they are bigger than the icon's background.
Get it now?
Customize it! I'm not even going to TELL you what I did, so that you can be more creative, but as a tip I'll say Arial Black, X brushes, and tiny text work really well!
Aaaaaand you're done! I'd love to see what everyone can come up with! Also, please tell me if something's unclear. This style was used on such icons as...