File Extension VMG File Format Image file format VMG stands for Image file format. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Windows Imaging Format (WIM) MrSID (Multi-resolution Seamless Image Database) How are the graphics and images stored when you save a worksheet as a web page in Excel?