No subject

only 5*5 covers the image. I have tried to illustrate this in the
below figure:

http://img26.imageshack.us/img26/5585/nodes.jpg

But in that case only the pixels in the image that are located between
the 3. and 4. BSpline node will have full support. But is that not
wrong?

To my understanding a correct approach would be to specify 3 extra
nodes outside the image on both sides. I have tried to illustrate this
below:

http://img21.imageshack.us/img21/2756/nodes2.jpg

Using this BSpline grid will gurantee that all pixels in the image
will have full support.