The pressure $p$ depends solely on the height $h$, If $p_o$ is the atmospheric pressure, then:
$$p=p_0+\rho gh$$
Where $\rho$ is the liquid's density and $g\approx10\:\mathrm{ms^{-2}}$.
So for the left hand side tank the pressure would be slightly higher because the tank is taller (not because it has higher capacity).