Oh, I remember how to do it! I don't have photoshop in front of me, or on this computer, though, so the directions may be a bit vague, but here goes! Ok, first, make a circle with the shape towel thing. Have this on it's own layer from the rest of the picture. Select the layer in the list of your layers, and select 'layer properties' (I believe what you want is called that). This should bring up a kind popup menu thing with different things you can do to the layer. You can change the opacity, set of the layer (multiply, color, overlay, etc) on here. There will be a list on the left of different things you can do. Go to the bottom most one, and click on it twice so it brings you to a new set of things to mess with. I don't remember what it's called, but by messing around with this you create outlines to whatever is on the layer. This means you can set it to outline everything with black, and then all you have to do is make more circle shapes on the layer, and they will just instantly have the outline.

Hope you're able to figure all that out! If you can't decifer it, call me sometime when you're infront of your comp, and I can direct you through it.

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In the Galactic Republic, the Force uses YOU!

Woo! My hero!

You were clearly absent when God handed out innate knowledge of Photo-shop: Shapes... [If I remember correctly you were hiding behind the door.]