OH I know what you did XD WOokie mistake my friend. Just press ctrl+z and it should undo. You probably had the scale too high, yes, you say there was no resize thing, but trust me, all it is is that under the toolbar, well, technically it IS in the toolbar, but it is below the rest of it, should be a little box with random stuff in it. One of the little scroll bars says "Opacity" and the other is "scale". For skin making, use 1 pixel.You may not have seen it at first, but it is there! Trust me, I am a pro when it comes to GIMP!