Update for ranges.

I actually really need to have 2 frame widths on right/down direction
too to allow for rotation before animating in, so the range
interpretation will be:

0 = top/left 2 frame widths left/up
0.2 = top/left 1 frame width left/up
0.4 = top/left aligned with dest image
0.6 = top/left just out of dest image bottom/right corner
0.8 = top/left 1 frame width down/right
1.0 = top/left 2 frame widths down/right


Janne