well, take a look at these Icons. All you have to do, is rightclick and save as, then upload, overwritting the old ones. They will look much better, on a dark board. Visit HERE to see them in action.
They are original IPB 2.0 default Icons, but modified for dark boards.
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PS: I got a better made post icons, if you need them, just take them off my board. They look better around the edges.