When ultrashort and intense laser pulses are focused onto an atomic gas, different ionic charge states are generated upon multiple photoionization. The spatial distribution of the different charge states depends on the intensity distribution in the laser focus. By spatially resolving the charge state distribution, our ion microscopy technique provides access to intensity resolved ion yields. The technique is particularly well suited to studying ultrafast light-matter interactions in the XUV spectral range. It has recently allowed the first demonstration of nonlinear interactions between attosecond XUV pulses and core electrons in xenon.