The ability to nondestructively image living organisms, examine biological materials, and inspect packages without the necessity of removing the contents are applications well suited to x-ray radiography. We have developed a portable flash x-ray (FX) source having adjustable peak x-ray photon energy, which delivers a 34 milliroentgen rr-ray dose at 30 cm in a 60-ns full-width at half-maximum (FWHM) pulse using less than 5 joules of stored energy. This technology has generated considerable interest in the biomedical imaging community and promises to replace older x-ray systems that were not readily portable.