  We have developed an inversion procedure designed for high-resolution solar
spectro-polarimeters, such as Hinode/SP or DKIST/ViSP. The procedure is based
on artificial neural networks trained with profiles generated from random
atmospheric stratifications for a high generalization capability. When applied
to Hinode data we find a hot fine-scale network structure whose morphology
changes with height. In the middle layers this network resembles what is
observed in G-band filtergrams but it is not identical. Surprisingly, the
temperature enhancements in the middle and upper photosphere have a reversed
pattern. Hot pixels in the middle photosphere, possibly associated to
small-scale magnetic elements, appear cool at the log(tau_500)=-3 and -4 level,
and viceversa. Finally, we find hot arcs on the limb side of magnetic pores,
which we interpret as the first direct observational evidence of the "hot wall"
effect in temperature.
