In this work we show how energy-filtered imaging can be used to obtain spectrum images of electron energy-loss spectrometric data. Focus is placed on improved energy resolution within these data sets. Using two multilayer samples (GaN/AlN and InP/InAs), we demonstrate the advantages of spectrum-imaging and its extended mapping capabilities. Plasmon-ratio maps are used to quickly create high-contrast material maps with high signal-to-noise ratio, ratio-contrast plots are used to gain optimum settings for the ratio maps, and plasmon-position maps are used to map small shifts of the energy position of bulk plasmon peaks.