  In a recent paper, Altenbernd, Thomas and W\"ohrle have considered acceptance
of languages of infinite two-dimensional words (infinite pictures) by finite
tiling systems, with the usual acceptance conditions, such as the B\"uchi and
Muller ones, firstly used for infinite words. The authors asked for comparing
the tiling system acceptance with an acceptance of pictures row by row using an
automaton model over ordinal words of length $\omega^2$. We give in this paper
a solution to this problem, showing that all languages of infinite pictures
which are accepted row by row by B\"uchi or Choueka automata reading words of
length $\omega^2$ are B\"uchi recognized by a finite tiling system, but the
converse is not true. We give also the answer to two other questions which were
raised by Altenbernd, Thomas and W\"ohrle, showing that it is undecidable
whether a B\"uchi recognizable language of infinite pictures is E-recognizable
(respectively, A-recognizable).
