  All-optical Compton sources are innovative, compact devices to produce high
energy femtosecond X-rays. Here we present results on a single-pulse scheme
that uses a plasma mirror to reflect the drive beam of a laser plasma
accelerator and to make it collide with the highly-relativistic electrons in
its wake. The accelerator is operated in the self-injection regime, producing
quasi-monoenergetic electron beams of around 150 MeV peak energy. Scattering
with the intense femtosecond laser pulse leads to the emission of a collimated
high energy photon beam. Using continuum-attenuation filters we measure
significant signal content beyond 100 keV and with simulations we estimate a
peak photon energy of around 500 keV. The source divergence is about 13 mrad
and the pointing stability is 7 mrad. We demonstrate that the photon yield from
the source is sufficiently high to illuminate a centimeter-size sample placed
90 centimeters behind the source, thus obtaining radiographs in a single shot.
