A file to store presentations with tables, drawings, texts, audio and video created using open source programs: OpenOffice, StarOffice, LibreOffice, etc. The file is editable and based on the XML format. Is an open alternative to the closed PPT format.
PNG is a raster graphic data storage format that uses lossless compression algorithm to Deflate. PNG was created as a free format to replace GIF. PNG supports three main types of raster images: grayscale image, a color indexed image and the color image. PNG format stores graphical information in a compressed form.