A cassette or an analogous supports for sheet-like X-ray films has a bottom wall and a top wall which latter is connected to the bottom wall by a hinge. One of the walls carries a magnetic plate which is overlapped by a first intensifier screen for the X-ray film. The other wall carries a flat flexible receptacle for a ferromagnetic layer therewithin, and the receptacle is overlapped by a second intensifier screen. When a film is inserted between the two screens, the cassette is closed whereby the magnetic layer attracts the ferromagnetic layer with the result that the two screens are biased against the respective sides of the film therebetween. The second screen may constitute an integral part of the receptacle which latter consists of a material, such as paper or synthetic plastic, that is permeable to X-rays. The receptacle forms part of or constitutes a laminate and is floatingly mounted at the inner side of the other wall so that, when the two walls are moved close to each other and the magnetic layer attracts the ferromagnetic layer, the laminate compensates for eventual manufacturing tolerances of the cassette.