I'll say. How'd you do it?
My good friend, the smudge tool. It's the tool that looks like a hand with one finger pointing downward, at least in my version of Photoshop. To extend pieces (like the tail in mine) you make sure "preserve transparency" (located right above the layers list) is turned off, and smudge with a fairly solid brush at 100% pressure. To clean up spots inside a shape, turn "preserve transparency" on, then... well, you have to experiment a bit. If the shape is a fairly flat colour with a spot on it that you don't want, a solid shape, 100% pressure, will usually be okay. If you have a scattered effect that you want to get rid of, a softer brush with a small amount of pressure (25% is my low pressure default) is good, and you kind of scirbble randomly in the area you want to normalise. Try to follow pre-existing patterns, and be sure not to smudge around the bits you are trying to remove.
Newer versions of Photoshop have a wonderful thing called "clone" which lets you select a small area, and then copy that bit all over a larger area. I wish I had that tool...
Ah, thank you, sir. I have now officially adopted you as my picture edit sensai.
I tried to find a patch for the clone command to thank you for the nice explanation, but alas, no luck. :(
So instead I give you boorite's Mastercard number: 09328-234922-10293
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I ate a hooker half a bottle of knife.