  We have recorded the coherent diffraction images of individual xenon clusters
with intense extreme ultraviolet pulses to elucidate the influence of
light-induced electronic changes on the diffraction pattern. Using the FLASH
free-electron laser we tuned the wavelength to specific xenon atomic and ionic
resonances. The data show the emergence of a transient core-shell structure
within the otherwise homogeneous sample. Simulations indicate that ionization
and nanoplasma formation result in a cluster shell with strongly altered
refraction. The presented resonant scattering approach enables imaging of
ultrafast electron dynamics on their natural time scale.
