We present results of preheat of thin foils heated by laser at 0.26 μm. The emission of the rear of the thin foils is imaged with the use of two Schwartzchild microscopes at 80 eV and 40 eV. These microscopes made of multilayered mirrors have a large aperture (f/2.5) and a good spatial resolution (5 μm) for a total reflec-tivity of about 1 %. The time integrated two dimensional images and time resolved images are shown. From the records at these two wavelengths we are able to deduce the temperature of the rear of the foils and its spatial distribution inside the heated surface of the foils.