Images of the Spring-8 Angstrom Compact free electron LAser (SACLA) 10 keV pulsed (10 fs) beam were recorded in a lithium fluoride (LiF) crystal by exploiting visible photoluminescence of radiation-induced color centers (CCs). Photoluminescent beam images stored in LiF, irradiated at several energies from 0.04 to 0.8 J, were acquired by a fluorescence optical microscope and processed with an algorithm developed in Matlab, allowing to reconstruct the transversal beam fluence distribution.