ok, heres the "big" image:

and this is the sub-image

the position of the subimage is (30,0) and the size is (5,5)
the code is rather straight forward:
on startup i set texture mag-filter to GL_NEAREST
then i call some glTranslate and glScale methods
and then draw the quad.
one thing is, if i set the position of the subimage in the source-image not to the exact borders of the sub-image but one pixel more to the right and reduce the width by two, so that the left and right neighbour pixels of the sub-image are also red [position(31,0) size(3,5)] , then the streching is right, but that is no solution, because i would have to set up this offset for every tile individually.
knoggly