Recently someone had sent an JPG Image over , however on opening the image from Outlook with Windows 7’s  Photo Viewer it was showing the image as a slide show of five seperate images.Initially confused ( as a TIF is the only mulipage image format ), I thought the slideshow program was being clever and scanning through my Temp Folder and displaying all the photos in that folder, however upon reopening the image from a new location this was not the case. I opened the image up with tools such as Microsoft Office Picture Manager and Paint , and only the first page showed. Upon dragging the image into Infran Viewer, it straight away told me the image was infact a TIF image and would I like to change the file extension! I was amazed Windows opened these fine without trying to decode these as jpg instead of TIFS. So you can fool windows into thinking there are multipage jpgs, could be useful for accountants scanner in and archiving documents!