  The extremely bright optical flash that accompanied GRB 080319B suggested, at
first glance, that the prompt $\gamma$-rays in this burst were produced by
Synchrotron self Compton (SSC). We analyze here the observed optical and
$\gamma$ spectrum. We find that the very strong optical emission poses, due to
self absorption, very strong constraints on the emission processes and put the
origin of the optical emission at a very large radius, almost inconsistent with
internal shock. Alternatively it requires a very large random Lorentz factor
for the electrons. We find that SSC could not have produced the prompt
$\gamma$-rays. We also show that the optical emission and the $\gamma$ rays
could not have been produced by synchrotron emission from two populations of
electron within the same emitting region. Thus we must conclude that the
optical and the $\gamma$-rays were produced in different physical regions. A
possible interpretation of the observations is that the $\gamma$-rays arose
from internal shocks but the optical flash resulted from external shock
emission. This would have been consistent with the few seconds delay observed
between the optical and $\gamma$-rays signals.
