  We investigate sharp structures visible in solar magnetic field tracers. It
is shown that the sunspot magnetic boundaries do not coincide with the
photometric ones. Moreover, there is no clear boundary of the magnetic field in
the vicinity of sunspots. Thus, the widely accepted concept of magnetic tubes
with sharp edges is not always correct and should be used with caution. It is
also shown that even in the moments of complete absence of visible spots on the
Sun, there are magnetic fields over 800 Gauss. The nature of these strong
magnetic fields remains unclear; they may originate at relatively small depths
under the photosphere.
