  We image spatial distributions of Xe$^{q+}$ ions in the focus of a laser beam
of ultrashort, intense pulses in all three dimensions, with a resolution of
$\sim$3 $\mu$m and $\sim$12 $\mu$m in the two transverse directions. This
allows for studying ionization processes without spatially averaging ion
yields. Our \emph{in situ} ion imaging is also useful to analyze focal
intensity profiles and to investigate the transverse modal purity of tightly
focused beams of complex light. As an example, the intensity profile of a
Hermite-Gaussian beam mode HG$_{1,0}$ recorded with ions is found to be in good
agreement with optical images.
