This is a bug with image burn verison 2.4.4.0 in Window 7 RC candidate file version 7100
I wanted the Windows 7 Repair disk that Win 7 burns, but as an ISO image, for Virtual use.. I down loaded the latest version [and did not use my save copies, I have versions 1.1.0.0 all the way up vers 2.4.2.0. I guess I didn't down load 2.4.3.0 I will check on that.], And every time I tried to read it to an ISO file it would automaticly change to and .img file went it started saving the file.
I look at all the Settings and I couldn't see anything that would cause that. I uninstalled version 2.4.4.0 and installed version 2.4.2.0 and tried it. No Problem. It read the disk to an ISO file.
I will down load version 2.4.3.0 and see if it works ok as well. and update with a new post.
Many thanks for a great Burning program. Oh, an the other programs too.