无扩展的图像文件在IIS7.5中不可见

We have extension less images which worked perfectly in iis6. However, in IIS7.5 even after adding the static file handler i am not able to get it to display the image. I have ticked the Static content option in properties for IIS7.5 the operating system for server is Windows Server 2008 R2. The image file with extension are visible properly. However those without extension give me 404 in fiddler. The mime type application/octet-stream has also been added for .* filename extensionWe have extension less images which worked perf