I find this very annoying. If I want to put an image in the body of my text, people who have not upgraded to 7 or who cannot afford to upgrade only see a .dat file, no photo. I have a sister with a Mac who cannot see inserted images either and a brother and several friends with older computers. I have to remember who is who or attach and insert images.
I don't like it that users of older operating systems are being left out.