  In this paper, we detail and complete the existing characterizations of the
decimation of the Ising model on $\Z^2$ in the generalized Gibbs context. We
first recall a few features of the Dobrushin program of restoration of
Gibbsianness and present the construction of global specifications consistent
with the extremal decimated measures. We use them to consider these
renormalized measures as almost Gibbsian measures and to precise its convex set
of DLR measures. We also recall the weakly Gibbsian description and complete it
using a potential that admits a quenched correlation decay, i.e. a well-defined
configuration-dependent length beyond which this potential decays
exponentially. We use these results to incorporate these decimated measures in
the new framework of parsimonious random fields that has been recently
developed to investigate probability aspects related to neurosciences.
