So you ARE talking of DosBOX :tai:
If you want to animate, get
AnimGet, start it, klick "Capture", then switch to your DOSBox window and let the animation play. You now should have a lot of pics. Make a *.gif out of it with a program of your choice (don't know any, google for it).
Edit:
There may be better methods, but that is how I would do it.