We study the Foppl-von Karman theory for isotropically compressed thin plat
es in a geometrically linear setting, which is commonly used to model weak
buckling of thin films. We consider generic smooth domains with clamped bou
ndary conditions, and obtain rigorous upper and lower bounds on the minimum
energy linear in the plate thickness sigma. This energy is much lower than
previous estimates based on certain dimensional reductions of the problem,
which had lead to energies of order 1 + sigma (scalar approximation) or si
gma (2/3) (two-component approximation).