  We give a detailed account of the theoretical analysis and the experimental
results of an x-ray-diffraction experiment on quantum-state selected and
strongly laser-aligned gas-phase ensembles of the prototypical large asymmetric
rotor molecule 2,5-diiodobenzonitrile, performed at the Linac Coherent Light
Source [Phys. Rev. Lett. 112, 083002 (2014)]. This experiment is the first step
toward coherent diffractive imaging of structures and structural dynamics of
isolated molecules at atomic resolution, i. e., picometers and femtoseconds,
using x-ray free-electron lasers.
