Cut-Paste across stacks ?

[Richmond]

If one has a stack with, for example, 2 substacks, one of
which contains an image "X.png".

Now I want to move image "X.png" from substack "sONE"
to substack "sTWO".

sending the command  cut img "X.png"  seems all very straightforward . . .

BUT . . .

while I can issue the command  paste

how can I ensure that the clipboard contents (i.e. img "X.png") are
pasted into substack "sTWO" rather than abck into substack "sONE" ?

Richmond.