toritori9:
Use the offset function. In photoshop it's filter->other->offset
since it's on the inside area and you want it facing out, an offset of +64 vertical would do it.
I also assume that the legs are sposed to be mirrored to each other yeah?
So the procedure for mirroring legs and thighs is to flip vertical then offset 64 pixels down.
Nice designs btw
@aaron in addition to what hanz0 said, you may also want to feather your selection a bit (maybe 0.5 pixels) to create makeshift antialiasing (reduces sharp edges)