Gimp image pasting

[Dominar]

So, I'm new to the whole skinning thing but have some general knowledge with simple coding. I'm terrible at images and was wondering if it's possible to simply use a working image and cut the old image off a layer and copy a new image onto the layer as to avoid having to play with alpha channels as after 2 weeks I still can't grasp this concept.

Any help would be great on this.

Great site and forums, you guys and girls definetely sucked me into this thing and I'm determined to figure this out even if my brain explodes