Hi,
are you using a special skin? It's likely a mis use of the gui stuff.
gui layout will adapt size to whyt you tell it to be, not with what image you are injecting in it. It really depends how you are building this.
as for preview, are you sure you have selected the state where you have some gui in it? it only show the preview of gui actions within a the selected state.
If in trouble, pm me, I'll look over this.
bye,
Jean