DjVu, pronounced as “déjà vu”, is a graphics file format intended for scanned documents and books especially those which contain the combination of text, drawings, images and photographs. It was developed by AT&T Labs. It uses multiple techniques like image layer separation of text and background images, progressive loading, arithmetic coding and lossy compression for bitonal images
EMZ is a file extension for a compressed graphics file used by the Microsoft Office Suite and Visio. Stands for Enhanced Metafile-Zipped. Contains an EMF (Enhanced MetaFile) image file that has been compressed using GZIP compression.