1. Goto Control Panel and double click on 'Folder Options'.
2. Goto the 'File Types' tab.
3. Locate the raster file extension inside the 'registered file types' list
4. If the extension does not exist, then click on 'New' to create a new one.
5. Select the extension from the list and click on 'Change' button shown in the details section.
6. From the next popup window, choose 'Select the program from a list' option.
7. Choose Autodesk DWF Application as the preferred application to open files with this extension. Also remember to check the 'Always use the selected program to open this kind of file' check box shown right under the list.
8. If everything is done properly, it will look as shown in the image below.
That's it. Repeat the same steps for other types of raster files. Once done, you don't have worry about it any more. Now you can goto explorer and double click those files to open it directly inside the Design Review application. I have configured mine to view file types like CAL, CALS, GP4, CG4, MIL, RST, PCT, PICT, TGA, RLS etc. (testing pending for some types). The best part of the story is that you can easily save this image as a DWF(x) file in order to send it to somebody for review purpose.
Autodesk Design Review is a wonderful review application with exciting features like '2D content comparison', 'PDF Support' etc. It's free and can be downloaded from the Autdesk Design Review site.